Electroluminescent device and process for producing the same

ABSTRACT

An EL device comprising a first electrode, an EL layer formed on the first electrode, and a second electrode formed on the EL layer, wherein at least one layer of a material whose wettability changes when light is applied thereto is formed. The invention provides EL devices that can be simply produced, and processes for producing the same.

TECHNICAL FIELD

[0001] The present invention relates to electroluminescent devices(hereinafter referred to as EL devices), especially organic thin-film ELdevices, useful for displays, and to processes for producing the same.

BACKGROUND

[0002] There is a great deal of interest in the application of ELdevices to spontaneous-emission panel displays. In particular, organicthin-film EL displays using organic substances as luminous materialsemit light of high luminance even at low applied voltages of not morethan 10 V, and thus show excellent luminous efficiencies. Moreover,these displays can emit light even when the EL devices used have simplestructures. There is therefore such a hope that organic thin-film ELdisplays be applied to high-resolution full-color displays, or toinexpensive simple displays that are used for displaying fixed patternsfor advertisement or the like by the emission of light.

[0003] The production of displays using EL devices practically requiresthe patterning of electrodes and of organic EL layers, and typicallyincludes a photolithographic process, or a patterning process using acomplicated system for pattern-wise depositing films. Such productionprocesses are complicated, and bring about increase in production cost.Further, a process in which an organic EL film is formed pattern-wise bydeposition using a mask requires a vacuum apparatus, which is expensive.Problems with this process are decrease in yield, and increase in cost.On the other hand, a process in which patterns are formed by an ink jetprocess includes steps that are relatively simple; however, this processhas the problems of decrease in yield and in evenness of film thickness.In addition, EL devices for displaying patterns for advertisement arerequired to take various shapes and to have greatly increased surfaceareas. The production of such EL devices is confronted with the problemof remarkable decrease in productivity.

[0004] Thus, the production of EL devices, especially that of organic ELdisplays, includes the patterning of electrodes, organic EL layers,insulating layers, etc., so that it inevitably includes a considerablygreat number of steps. The production of EL devices, therefore, hasproblems awaiting solution on yield, productivity and cost. In addition,it is important to increase the pattern accuracy of a luminous layer inorder to improve displaying properties, so that it is necessary toaccurately provide, on an electrode, a luminous layer with a uniformthickness.

[0005] An object of the present invention is to provide an EL devicethat can be produced more simply than ever, and a process for producingthe same; in particular, an EL device whose constituent layers such as aluminous layer and a partitioning layer have excellent pattern accuracyand which emits light with high uniformity, and a process for producingsuch an EL device.

DISCLOSURE OF THE INVENTION

[0006] We found that the aforementioned problems in the prior art can besolved by applying light pattern-wise to a layer of a material whosewettability changes when light is applied thereto, thereby forming onthe layer a latent pattern due to the difference in wettability, andthen forming an EL layer, a partitioning layer, an insulating layer, afirst electrode, a second electrode, etc. by utilizing this latentpattern. The present invention was accomplished on the basis of thisfinding.

[0007] Accordingly, the present invention is an EL device comprising afirst electrode, an EL layer formed on the first electrode, and a secondelectrode formed on the EL layer, characterized by being provided withat least one layer of a material whose wettability changes when light isapplied thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0009]FIG. 2 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0010]FIG. 3 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0011]FIG. 4 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0012]FIG. 5 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0013]FIG. 6 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0014]FIG. 7 is a cross-sectional view showing the structure of one ELdevice of the present invention.

[0015]FIG. 8 is a cross-sectional view for illustrating one process forproducing an EL device according to the present invention.

[0016]FIG. 9 is a cross-sectional view for illustrating one process forproducing an EL device according to the present invention.

[0017]FIG. 10 is a cross-sectional view for illustrating one process forproducing an EL device according to the present invention.

[0018]FIG. 11 is a graph showing the light emission properties of the ELdevices of Example D-1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0019] EL devices

[0020] As mentioned above, the EL device of the present inventioncomprises a first electrode, an EL layer formed on the first electrode,and a second electrode formed on the EL layer, and is characterized bybeing provided with at least one layer of a material whose wettabilitychanges when light is applied thereto, such as aphotocatalyst-containing layer. The EL device of the present inventionmay comprise optional layers that are usually provided in conventionalEL devices. In the case where the EL device is a full-color display inwhich fine picture elements are formed by patterning, the effects of theinvention can fully be obtained.

First Embodiment

[0021]FIG. 1 is a cross-sectional view showing one example of the ELdevice according to the present invention. This EL device has thefollowing structure: a first electrode 2, a photocatalyst-containinglayer 3, an EL layer 5 and a second electrode 6 are laminated to asubstrate 1 in the order mentioned, and another EL layer 4 is formedbetween the wettability-changed part 3, of the photocatalyst-containinglayer 3 and the EL layer 5.

Second Embodiment

[0022]FIG. 2 is a cross-sectional view for illustrating a first ELdevice according to the second embodiment of the present invention. Inthis figure, reference numeral 21 indicates a patterned first electrode;reference numeral 24, a patterned second electrode; reference numeral22, a wettability-changeable material layer; reference numeral 23, aluminous layer; reference numeral 26, a substrate; and reference numeral29, an insulating layer.

[0023] As shown in FIG. 2, the first EL device according to the secondembodiment of the present invention has the following structure: theluminous layer 23 corresponding to the pattern of the first electrode 21is sandwiched between the two patterned electrodes 21, 24, and thewettability-changeable material layer 22 is provided between thepatterned first electrode 21 and the luminous layer 23.

[0024] The wettability-changeable material layer 22 is firstly laminatedto the substrate 26 on which the first electrode 21 and the insulating29 have been provided, and light is then applied to the layer 22 througha mask having the same pattern as that of the first electrode 21, or amask having openings that are larger than the border of the patternedfirst electrode 21. In the course of this process, a part of thewettability-changeable material layer 22 that corresponds to the borderof the patterned first electrode 21 becomes an exposed part havingincreased wettability against the laminating material, while a part ofthe wettability-changeable material layer 22 that corresponds to thepart where the border of the patterned first electrode 21 do not existbecomes an unexposed part. The luminous layer 23 is formed pattern-wiseby utilizing the difference in the wettability against the laminatingmaterial, which is a luminous-layer-forming material, between theexposed part and the unexposed part of the wettability-changeablematerial layer 22. In order to prevent short circuit, it is hereinpreferable to cover, with the insulating layer 29, the edges of theborder of the patterned electrode 21 and those parts that are betweenthe borders of the same.

[0025] By referring now to FIG. 3, a second EL device according to thesecond embodiment of the present invention will be described. The ELdevice shown in FIG. 3 is the same as that shown in FIG. 1 except that apartitioning layer 37 is formed between the borders of a patternedluminous layer 33. With this partitioning layer, continuity across thetwo electrodes can be prevented more reliably. To form the partitioninglayer, a polymeric organic material, preferably an ultraviolet-curingresin, having a resistance of 10⁷ Ω.cm or more is used. Further, if thepartitioning layer is made to have a dark color such as black, theresulting EL device can display a pattern more sharply. The partitioninglayer 37 is formed so that its thickness will be between 0.1 μm and 10μm, preferably between 1 μm and 2 μm.

[0026] To make the EL device shown in FIG. 3, a wettability-changeablematerial layer 32 is formed after forming pattern-wise an electrode 31and an insulating layer 39. Subsequently, only a part of thewettability-changeable material layer 32 that corresponds to the partbetween the borders of the patterned electrode 31 is exposed to light,thereby making the surface of this part an exposed part. When a materialfor forming the partitioning layer is applied by uniform coating or thelike, it adheres only to the exposed part. In the case where anultraviolet-curing resin is used as the material for forming thepartitioning layer, ultraviolet light is uniformly applied to the resinto cure it, and, at the same time, to change a part of thewettability-changeable material layer that corresponds to the border ofthe patterned electrode to an exposed part. Subsequently, a luminouslayer is formed by the use of an ink jet process or the like as in theproduction of the EL device shown in FIG. 2, thereby obtaining thedesired EL device. In order to prevent crosstalk between the borders ofthe patterned electrode 21, it is preferable to cover, with aninsulating layer 39, the edges of the border of the patterned electrode21 and those parts that are between the borders of the same.

[0027]FIG. 4 shows an EL device that is the same as the one shown inFIG. 2 except that a wettability-changeable material layer 42 isprovided on a substrate 46. Since the EL device shown in FIG. 4 has sucha structure, it is excellent in pattern accuracy. Thewettability-changeable material layer 42 may also be provided on aluminous layer 43. Thus, the wettability-changeable material layer maybe provided at any position as long as the injection of charges is notinhibited. Moreover, this layer may be composed of either a single layeror multiple layers.

[0028] The EL device shown in FIG. 4 can be made in the followingmanner. After uniformly forming the wettability-changeable materiallayer 42 on the substrate 46, light is applied only to a part of thelayer 42 on which an electrode is supposed to be formed, and a materialfor forming the electrode is sputtered on this exposed part.Subsequently, a material for forming a luminous layer is applied byuniform coating, whereby the luminous layer is formed only on theelectrode. Thereafter, only a part of the wettability-changeablematerial layer that is between the borders of the patterned luminouslayer is exposed to light to make it an exposed part, and a material forforming a partitioning layer is applied to the exposed part by an inkjet process or the like to form a partitioning layer. An EL device canthus be obtained as in the case of the EL device shown in FIG. 2. The ELdevice shown in FIG. 4 is excellent in pattern accuracy like the ELdevices shown in FIGS. 2 and 3. Moreover, this EL device is alsoexcellent in injection of charges from the electrodes 41,44 to theluminous layer, so that it has high luminous efficiency.

[0029] The luminous layer may be a mono-colored, patterned layer.Alternatively, luminous layers of R, G and B may be alternately andsequentially laminated to the wettability-changeable material layer toobtain a full-color structure. Each luminous layer can be laminated inthe following manner: (1) anode/wettability-changeable materiallayer/hole-injection layer (buffer layer)/luminouslayer/electron-transfer layer/electron-injection layer (bufferlayer)/cathode, or (2) anode/hole-injection layer (buffer) /luminouslayer/electron-transfer layer/electron-injection layer (bufferlayer)/wettability-changeable material layer/cathode.

[0030] In the above (1) and (2), instead of separately forming thecharge-injection layer, the charge-transfer layer and the luminouslayer, one layer may be formed by the use of a material having all ofthe functions of these layers. Alternatively, a mixture of materials,each having one of the functions may be used.

Third Embodiment

[0031] The third embodiment of the present invention is an EL devicecapable of displaying, by the emission of light, a pattern that isdifferent from the patterns of two facing electrodes. To produce this ELdevice, it is not necessary to conduct the patterning of electrodes, sothat the production process becomes simpler. Further, the EL deviceaccording to the third embodiment of the present invention may containat least one photocatalyst-containing layer between the two facingelectrodes. This layer is provided in order to simplify the productionprocess, and surprisingly, it never mars the light emission propertiesof the EL device even when it is made from an insulating material.

[0032] A first mode of the pattern-wise emission of light by the ELdevice of the present invention is as follows: an EL layer is formedpattern-wise on a photocatalyst-containing layer, and this patterned ELlayer is caused to emit light. Although this EL layer encompasses, asmore specific concept, charge-injection layers (a hole-injection layerand an electron-injection layer), charge-transfer layers (ahole-transfer layer and an electron-transfer layer), and a luminouslayer, it is herein enough to pattern at least one of these layers. Forinstance, the EL device may have a photocatalyst-containing layer onanode, a patterned hole-injection layer on the photocatalyst-containinglayer, and a luminous layer provided on the entire-surface of thehole-injection layer regardless of its pattern. The following is alsoacceptable: a luminous layer is formed pattern-wise, and anotherluminous layer whose color is different from that of the patternedluminous layer is provided on the entire surface of the patternedluminous layer. By doing so, the resulting EL device can display apattern by the emission of light while emitting light from its entiresurface.

[0033] A second mode of the pattern-wise emission of light by the ELdevice of the present invention is as follows: an insulating layer isformed pattern-wise on a photocatalyst-containing layer, and thenon-insulated part of an EL layer is caused to emit light.

[0034]FIG. 5 is a cross-sectional view showing the structure of one ELdevice according to the third embodiment of the present invention. Inthis EL device, a first electrode 52, a photocatalyst-containing layer53 and a second electrode 55 are provided on a substrate 1 in the ordermentioned, and between the second electrode 55 and thephotocatalyst-containing layer 53, a luminous layer 54 is provided onlyon the part with which it is intended to attain pattern-wise emission oflight. Unexpectedly, it is possible, in such an EL device, to injectcharges into the luminous layer through the photocatalyst-containinglayer while preventing continuity across the first electrode 52 and thesecond electrode 55, thereby causing the luminous layer to emit light.

[0035]FIG. 6 is a cross-sectional view showing the structure of anotherEL device according to the third embodiment of the present invention. Inthis EL device, a first electrode 62, a photocatalyst-containing layer63, a luminous layer 64, and a second electrode 65 are provided on asubstrate 61 in the order mentioned, and between the luminous layer 64and the photocatalyst-containing layer 63, a charge-injection layer 66is provided only on the part with which it is intended to attainpattern-wise emission of light. In such an EL device, it is typical thatthe part where the charge-injection layer is formed emits light and thatthe part where the charge-injection layer is not formed does not emitlight. However, it is also possible to obtain an EL device in which thepart where the charge-injection layer is formed emits light, and thepart where the charge-injection layer is not formed also emits light butwith extremely low intensity.

[0036] Further, if another luminous layer is formed instead of thepatterned charge-injection layer shown in FIG. 6, the resulting ELdevice can attain the emission of light of two colors owing to thisluminous layer and the luminous layer formed on the entire surface ofthe device.

[0037]FIG. 7 is a cross-sectional view showing the structure of anotherEL device according to the third embodiment of the present invention. Inthis EL device, a first electrode 72, a photocatalyst-containing layer73 and a second electrode 75 are provided on a substrate 71 in the ordermentioned; and between the second electrode 75 and thephotocatalyst-containing layer 73, an insulating layer 79 is providedonly on the part that is not allowed to emit light, while a luminouslayer 74 is entirely provided.

[0038] The EL devices of the present invention can be used for variousapplications. For example, they are useful for nameplates, billboards,signboards, emergency/warning signs, road signs, the indication of fixedletters on clockfaces or on the indicators of meters, price tags, menus,leaflets, post cards, greeting cards, prepaid cards, paper-likedisplays, electronic books, lighting, toys for use in amusementfacilities and the like, the indication of logo marks, advertisingsignboards, calendars, displays, batch maps, and the indication of fixedpatterns such as map symbols and patterns (marks) whose shapesthemselves have particular meanings.

Fourth Embodiment

[0039] The EL device according to the fourth embodiment of the presentinvention is the same as the EL device of the first embodiment mentionedpreviously except that the photocatalyst-containing layer contains asubstance capable of improving light emission properties.

[0040] Layer of Material Whose Wettability Changes when Light Is AppliedThereto

[0041] The layer of a material whose wettability changes when light isapplied thereto for use in the present invention includesphotocatalyst-containing layers containing photocatalysts of a narrowsense, represented by photo-semiconductors such as titanium oxide, andspecific polymeric organic layers. In this specification, the term“photocatalyst-containing layer” and the term “layer of a material whosewettability changes when light is applied thereto” that includes theabove-described layers are sometimes used interchangeably.

[0042] Photocatalyst-Containing Layer

[0043] (Photocatalyst-containing layer)

[0044] In the present invention, the photocatalyst-containing layermeans a layer whose wettability will change when light is appliedthereto, or a layer whose wettability has already changed by theapplication of light. The photocatalyst herein may be any substance aslong as it can cause the above change in wettability. When thephotocatalyst-containing layer is subjected to pattern-wise exposure, alatent pattern due to the difference in wettability is formed on thephotocatalyst-containing layer. Typically, the unexposed part of thephotocatalyst-containing layer is water and/or oil repellent, while theexposed part of the same is highly hydrophilic and/or lipophilic. In thepresent invention, by utilizing this latent pattern due to thedifference in wettability, formed on the surface of thephotocatalyst-containing layer, those layers that are supposed to comeon the photocatalyst-containing layer (an EL layer, a first electrode, asecond electrode, etc.) are conveniently formed with high accuracy.

In First, Second and Third Embodiments

[0045] The photocatalyst-containing layer for use in the presentinvention can be provided at any position as long as it is between thesubstrate and the second electrode. For example, thephotocatalyst-containing layer may be provided between the substrate andthe first electrode, or between the first electrode and the EL layer(when the EL layer is composed of a plurality of layers, between theconstituent layers of the EL layer), or between the EL layer and thesecond electrode. It is however preferable to provide thephotocatalyst-containing layer between the first electrode and the ELlayer, thereby forming pattern-wise the EL layer by utilizing theabove-described latent pattern. In addition, not only one but also twoor more photocatalyst-containing layers may be formed. In the lattercase, it becomes easy to pattern, with high accuracy, a plurality oflayers that are formed on the photocatalyst-containing layers.

[0046] When the photocatalyst-containing layer is too thin, a cleardifference in wettability cannot be obtained, so that it is difficult toconduct the patterning of a layer that is provided on thephotocatalyst-containing layer. On the other hand, when this layer istoo thick, the transfer of holes or electrons is impeded, so that thelight emission of the resulting EL device is adversely affected. It istherefore preferable to make the thickness of thephotocatalyst-containing layer from 50 to 2000 angstroms, morepreferably from 100 to 1000 angstroms.

[0047] The thickness of the photocatalyst-containing layer may be in therange between 50 angstroms and 2000 angstroms as mentioned above. In thefirst EL device shown in FIG. 2, the photocatalyst-containing layer 22is effective for the pattern-wise formation of the luminous layer 23 onthe photocatalyst-containing layer 22, and, at the same time, serves asa layer preventing continuity across the electrodes 21 and 24 because ofits insulating properties. In EL devices, luminous layers are, ingeneral, extremely thin as compared with two electrode layers.Therefore, there is such a problem that continuity across the twoelectrodes easily takes place, for example, due to irregularity of theelectrode layers formed by vacuum deposition. Providing thewettability-changeable material layer can solve this problem. When theluminous efficiency of the luminous layer 23 is taken intoconsideration, it is necessary to ensure that charges can be injectedfrom the electrodes 21, 24 to the luminous layer 23 when voltage isapplied. It is therefore desirable to make the thickness of thewettability-changeable material layer not more than 1000 angstroms,which is the range of thickness that can make it possible to ensure theinjection of charges. The thickness of the wettability-changeablematerial layer may be from 100 to 1000 angstroms. In the case where theluminous layer is formed pattern-wise on the electrode through a bufferlayer and a charge-transfer layer as will be described later, these twolayers may respectively be formed pattern-wise on thewettability-changeable material layer in the same manner as in theformation of the luminous layer. In this case, the thickness of thewettability-changeable material layer may be determined by taking thetotal thickness of the wettability-changeable material layer, the bufferlayer and the charge-transfer layer, and the mobility of charges fromthe electrode to the luminous layer into consideration.

In Fourth Embodiment

[0048] In the fourth embodiment of the present invention, thephotocatalyst-containing layer contains a substance capable of improvinglight emission properties.

[0049] When the photocatalyst-containing layer is too thin, a cleardifference in wettability cannot be obtained, so that it is difficult toconduct the patterning of a layer that is provided on thephotocatalyst-containing layer. On the other hand, when this layer istoo thick, the transfer of holes or electrons is impeded, so that thelight emission of the resulting EL device is adversely affected.Therefore, the thickness of the photocatalyst-containing layer is madepreferably from 50 to 2000 angstroms, more preferably from 100 to 1000angstroms.

[0050] (Principle of Change in Wettability)

[0051] In the present invention, a latent pattern due to the differencein wettability is formed on the photocatalyst-containing layer byutilizing a photocatalyst that can cause adjacent substances (binders,etc.) to chemically react when light is applied. Although it is notclear how the photocatalyst acts, it is considered that the wettabilityof the surface of the photocatalyst-containing layer changes because thechemical structures of the binders and the like are directly changed bythose carriers produced in the photocatalyst when light is appliedthereto, or changed by active oxygen species produced in the presence ofoxygen and water.

[0052] (Photocatalyst Substance)

[0053] Examples of photocatalyst substances useful in the presentinvention include metallic oxides known as photo-semiconductors, such astitanium oxide (TiO₂), zinc oxide (ZnO), tin oxide (SnO₂).strontiumtitanate (SrTiO₃).tungsten oxide (WO₃), bismuth oxide (Bi₂O₃), and ironoxide (Fe₂O₃). Of these, titanium oxide is particularly preferred.Titanium oxide is advantageous in that it has high band gap energy, ischemically stable, has no toxicity, and is readily available.

[0054] Although both anatase titanium oxide and rutile titanium oxidecan be used as the photocatalyst in the present invention, anatasetitanium oxide is preferred. Specific examples of useful anatasetitanium oxides include an anatase titania sol of hydrochloric aciddeflocculation type (“STS-02” manufactured by Ishihara Sangyo Kaisha,Ltd., Japan, average crystal size: 7 nm), and an anatase titania sol ofnitric acid deflocculation type (“TA-15” manufactured by Nissan ChemicalIndustries, Ltd., Japan, average crystal size: 12 nm). These titaniumoxides are advantageous because they are excited by light having awavelength of not more than 380 nm.

[0055] It is preferable that the amount of the photocatalyst containedin the photocatalyst-containing layer be from 5 to 90% by weight, morepreferably from 20 to 60% by weight.

[0056] It is preferable that the particle diameter of the photocatalystbe small because a photocatalyst having a smaller particle diameter cancause photocatalytic reaction more effectively. It is preferable to usea photocatalyst having an average particle diameter of not more than 50nm, preferably of not more than 20 nm. In addition, when a photocatalysthaving a smaller particle diameter is used, the resultingphotocatalyst-containing layer has a smoother surface. When the surfaceroughness of the photocatalyst-containing layer exceeds 10 nm, theunexposed part of the photocatalyst-containing layer shows decreasedwater-repellency, and the exposed part cannot sufficiently revealhydrophilic nature.

[0057] (Binder Component)

[0058] Binders that can be used for the photocatalyst-containing layerof the present invention are preferably such materials that theirbackbone structures are not decomposed thanks to their high bondenergies even when the photo-excitation of the above-describedphotocatalysts occurs. Examples of such binders include (1)organopolysiloxanes having high strength, obtained by hydrolyzing andpolycondensing chlorosilane, alkoxysilanes, or the like through sol-gelreaction or the like; and (2) organopolysiloxanes excellent in water-and oil-repellency, obtained by crosslinking reactive silicones.

[0059] The organopolysiloxanes (1) may chiefly be hydrolyzed-condensedor co-hydrolyzed products of one of or two or more of silicon compoundsrepresented by the general formula Y_(n)SiX_(4-n) (n=1 to 3). In thisgeneral formula, Y may be an alkyl or fluoroalkyl group, or vinyl, aminoor epoxy group; and X may be halogen, or methoxyl, ethoxyl or acetylgroup.

[0060] Specific examples of the organopolysiloxanes (1) includemethyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane,methyltriethoxysilane, methyltriisopropoxysilane,methyltri-t-butoxysilane; ethyltrichlorosilane, ethyltribromosilane,ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane,ethyltri-t-butoxysilane; n-propyltrichlorosilane,n-propyltribromosilane, n-propyltrimethoxysilane,n-propyltriethoxysilane, n-propyltriisopropoxysilane,n-propyltri-t-butoxysilane; n-hexyltrichlorosilane,n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane,n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane;n-decyltrichlorosilane, n-decyltribromosilane, n-decyltrimethoxysilane,n-decyltriethoxysilane, n-decyltriisopropoxysilane,n-decyltri-t-butoxysilane; n-octadecyltrichlorosilane,n-octadecyltribromosilane, n-octadecyltrimethoxysilane,n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane,n-octadecyltri-t-butoxysilane; phenyltrichlorosilane,phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane,phenyltriisopropoxysilane, phenyltri-t-butoxysilane; tetrachlorosilane,tetrabromosilane, tetramethoxysilane, tetraethoxysilane,tetrabutoxysilane, dimethoxydiethoxysilane; dimethyldichlorosilane,dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxysilane;diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane,diphenyldiethoxysilane; phenylmethyldicholorosilane,phenylmethyldibromosilane, phenylmethyldimethoxysilane,phenylmethyldiethoxysilane; trichlorohydrosilane, tribromohydrosilane,trimethoxyhydrosilane, triethoxyhydrosilane, triisopropoxyhydrosilane,tri-t-butoxyhydrosilane; vinyltrichlorosilane, vinyltribromosilane,vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane,vinyltri-t-butoxysilane; trifluoropropyltrichlorosilane,trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane,trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane,trifluoropropyltri-t-butoxysilane;γ-glycidoxypropylmethyldimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-glycidoxypropyltriiethoxysilane, γ-glycidoxypropyltriisopropoxysilane,γ-glycidoxypropyltri-t-butoxysilane;γ-methacryloxypropylmethyl-dimethoxysilane,γ-methacryloxypropylmethyldiethoxysilane,γ-methacryloxypropyltrimethoxysilane,γ-methacryloxypropyltriethoxysilane,γ-methacryloxypropyltriisopropoxysilane,γ-methacryloxypropyltri-t-butoxysilane;γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilaneγ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,γ-aminopropyltriisopropoxysilane, γ-aminopropyltri-t-butoxysilane;γ-mercaptopropylmethyldimethoxysilane,γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane,γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane,γ-mercaptopropyltri-t-butoxysilane;β-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane, andβ-(3,4-epoxycyclohexyl)ethyltriethoxysilane; partially hydrolyzedproducts thereof; and mixtures thereof.

[0061] It is particularly preferable to use, as the binders,polysiloxanes containing fluoroalkyl groups. Specific examples of suchpolysiloxanes include hydrolyzed-condensed or co-hydrolyzed products ofone of or two or more of the following fluoroalkylsilanes, and thosepolysiloxanes generally known as fluorine-containing silane couplingagents may also be used.

[0062] CF₃(CF₂)₃CH₂CH₂Si(OCH₃)₃

[0063] CF₃(CF₂)₅CH₂CH₂Si(OCH₃)₃

[0064] CF₃(CF₂)₇CH₂CH₂Si(OCH₃)₃

[0065] CF₃(CF₂)₉CH₂CH₂Si(OCH₃)₃

[0066] (CF₃)₂CF(CF₂)₄CH₂CH₂Si(OCH₃)₃

[0067] (CF₃)₂CF(CF₂)₆CH₂CH₂Si(OCH₃)₃

[0068] (CF₃)₂CF(CF₂)₈CH₂CH₂Si(OCH₃)₃

[0069] CF₃(C₆H₄)C₂H₄Si(OCH₃)₃

[0070] CF₃(CF₂)₃(C₆H₄)C₂H₄Si(OCH₃)₃

[0071] CF₃(CF₂)₅(C₆H₄)C₂H₄Si(OCH₃)₃

[0072] CF₃(CF₂)₇(C₆H₄)C₂H₄Si(OCH₃)₃

[0073] CF₃(CF₂)₃CH₂CH₂SiCH₃(OCH₃)₂

[0074] CF₃(CF₂)₅CH₂CH₂SiCH₃(OCH₃)₂

[0075] CF₃(CF₂)₇CH₂CH₂SiCH₃(OCH₃)₂

[0076] CF₃(CF₂)₉CH₂CH₂SiCH₃(OCH₃)₂

[0077] (CF₃)₂CF(CF₂)₄CH₂CH₂SiCH₃(OCH₃)₂

[0078] (CF₃)₂CF(CF₂)₆CH₂CH₂SiCH₃(OCH₃)₂

[0079] (CF₃)₂CF(CF₂)₈CH₂CH₂SiCH₃(OCH₃)₂

[0080] CF₃(C₆H₄)C₂H₄SiCH₃(OCH₃)₂

[0081] CF₃(CF₂)₃(C₆H₄)C₂H₄SiCH₃(OCH₃)₂

[0082] CF₃(CF₂)₅(C₆H₄)C₂H₄SiCH₃(OCH₃)₂

[0083] CF₃(CF₂)₇(C₆H₄)C₂H₄SiCH₃(OCH₃)₂

[0084] CF₃(CF₂)₃CH₂CH₂Si(OCH₂CH₃)₃

[0085] CF₃(CF₂)₅CH₂CH₂Si(OCH₂CH₃)₃

[0086] CF₃(CF₂)₇CH₂CH₂Si(OCH₂CH₃)₃

[0087] CF₃(CF₂)₉CH₂CH₂Si(OCH₂CH₃)₃

[0088] CF₃(CF₂)₇SO₂N( C₂H₅)C₂H₄CH₂Si(OCH₃)₃

[0089] When one of the above-described polysiloxanes having fluoroalkylgroups is used as the binder, the unexposed part of the resultingphotocatalyst-containing layer has greatly increased water- andoil-repellency.

[0090] The above-described reactive silicones (2) include thosecompounds having backbone structures represented by the followinggeneral formula:

—(Si(R¹)(R²)O)_(n)—

[0091] wherein n is an integer of 2 or more, and R¹ and R² are asubstituted or unsubstituted alkyl, alkenyl, aryl or cyanoalkyl grouphaving 1 to 10 carbon atoms. The reactive silicones may containpreferably not more than 40% of vinyl, phenyl or halogenated phenyl.Further, those reactive silicones in which R¹ and/or R² are methyl groupare advantageous because such reactive silicones have minimum surfaceenergy. Preferable reactive silicones are those ones containing 60% ormore of methyl group, and, in their molecular chains, at least onereactive group such as hydroxyl group at their terminal ends or in sidegroups.

[0092] Together with the above-described organopolysiloxanes, stableorganosilicon compounds such as dimethylpolysiloxane that do not causecrosslinking reaction may also be incorporated into the binder.

[0093] (Substance Capable of Improving Light Emission Properties—inFourth Embodiment)

[0094] Any substance can be used as the substance capable of improvinglight emission properties that can be incorporated into thephotocatalyst-containing layer in the EL device according to the fourthembodiment of the present invention as long as it can improve the lightemission properties of the EL layer, for instance, a substance thatfacilitates the injection of holes or electrons to the EL layer such asthe luminous layer. Unexpectedly, even if the substance capable ofimproving light emission properties is added to thephotocatalyst-containing layer, the wettability of thephotocatalyst-containing layer after exposed to light is scarcelyaffected.

[0095] In the case where the photocatalyst-containing layer is providedbetween the EL layer and the anode, those substances capable ofimproving hole-injection properties conventionally added to ahole-injection layer or an anode buffer layer in an EL layer aretypically used as the substance capable of improving light emissionproperties. Examples of such substances include phenylamine compounds;star-burst-type amine compounds; phthalocyanine compounds; oxides suchas vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminumoxide; amorphous carbon; polyaniline; and polythiophene derivatives. Thesubstance capable of improving hole-injection properties is added in anamount of 10 to 90% by weight, more preferably 30 to 70% by weight sothat the function of the photocatalyst-containing layer will not beimpaired.

[0096] In the case where the photocatalyst-containing layer is providedbetween the EL layer and the anode, the following hole-transfersubstances can effectively be used as the substance capable of improvinglight emission properties.

[0097] <Hole-Transfer Substances> Oxadiazole compounds, oxazolecompounds, triazole compounds, thiazole compounds, triphenylmethanecompounds, styryl compounds, pyrazoline compounds, hydrazone compounds,aromatic amine compounds, carbazole compounds, polyvinylcarbazolecompounds, stylbene compounds, enamine compounds, azine compounds,triphenylamine compounds, butadiene compounds, polycyclic aromaticcompounds, stylbene dimers, and the like. Butadiene, enamine, hydrazoneand triphenylamine compounds are preferred because they have lowionization potentials. Hole-transfer substances include π-conjugatedpolymers such as polyacetylene, polydiacetylene, poly(p-phenylene),poly(p-phenylenesulfide), poly(p-phenyleneoxide), poly(1,6-heptadiyne),poly(p-phenylenevinylene), poly(2,5-thienylene), poly(2,5-pyrrole),poly(m-phenylenesulfide), and poly(4,4′-biphenylene). Examples ofhigh-molecular-weight charge-transfer complexes includepolystyrene.AgClO₄, polyvinylnaphthalene.TCNE,polyvinylnaphthalene.P-CA, polyphenylnaphthalene.DDQ,polyvinylmesitylene.TCNE, polynaphacetylene.TCNE,polyvinylanthracene.Br₂, polyvinylanthracene.I₂,polyvinylanthracene.TNB, polydimethylaminostyrene.CA,polyvinylimidazole.CQ, poly-p-phenyleneI₂.poly-1-vinylpyridine.I₂,poly-4-vinylpyridine.I₂, poly-p-1-phenylene.I₂, andpolyvinylpyridium.TCNQ. Further, examples of low-molecular-weightcharge-transfer complexes include TCNQ-TTF, and examples of metalcomplex polymers include copper polyphthalocyanine. The hole-transfersubstance is added to the photocatalyst-containing layer in an amount of10 to 90% by weight, more preferably 30 to 70% by weight so that thefunction of the photocatalyst-containing layer will not be impaired.

[0098] In the case where the photocatalyst-containing layer is providedbetween the EL layer and the cathode, those substances capable ofimproving electron-injection properties, conventionally added to anelectron-injection layer or a cathode buffer layer in an El layer aretypically used as the substance capable of improving light emissionproperties. Examples of such substances include lithium aluminate,lithium fluoride, strontium, magnesium oxide, magnesium fluoride,strontium fluoride, potassium fluoride, barium fluoride, aluminum oxide,strontium oxide, calcium, polymethyl methacrylate, and sodiumpolystyrenesulfonate. The substance capable of improvingelectron-injection properties is added to the photocatalyst-containinglayer in an amount of 10 to 90% by weight, preferably to 30 to 70% byweight so that the function of the photocatalyst-containing layer willnot be impaired.

[0099] It is effective to add the following color-developing agents,which are added to a luminous layer in a conventional EL layer, to thephotocatalyst-containing layer regardless of the position of thephotocatalyst-containing layer provided.

[0100] <Dyestuff Type> Cyclopentadiene derivatives, tetraphenylbutadienederivatives, triphenylamine derivatives, oxadiazole derivatives,pyrazoloquinoline derivatives, distyrylbenzene derivatives,distyrylarylene derivatives, silole derivatives, thiophene cycliccompounds, pyridine cyclic compounds, perynone derivatives, perylenederivatives, oligothiophene derivatives, trifumanylamine derivatives,oxadiazole dimers, and pyrazoline dimers.

[0101] <Metal Complex Type> Metal complexes, such as quinolinol aluminumcomplexes, benzoquinolinol beryllium complexes, benzoxazole zinccomplexes, benzothiazole zinc complexes, azomethyl zinc complexes,porphyrin zinc complexes, and europium complexes, having Al, Zn, Be,etc. or rare earth metals such as Tb, Eu and Dy as central metals, andoxadiazole, thiadiazole, phenyl pyridine, phenyl benzimidazole andquinoline structures, etc. as ligands.

[0102] <Polymer Type> Polyparaphenylene vinylene derivatives,polythiophene derivatives, polyparaphenylene derivatives, polysilanederivatives, polyacetylene derivatives, polyvinyl carbazole, andpolyfluorene derivatives.

[0103] If used, the color-developing substance is added to thephotocatalyst-containing layer in an amount of 10 to 90% by weight,preferably 30 to 70% by weight so that the function of thephotocatalyst-containing layer is not impaired.

[0104] It is also effective to add the following doping substances tothe photocatalyst-containing layer regardless of the position of thephotocatalyst-containing layer provided.

[0105] <Doping Substances> Perylene derivatives, coumarin derivatives,rubrene derivatives, quinacridone derivatives, squarium derivatives,porphyrin derivatives, styryl-based colorants, tetracene derivatives,pyrazoline derivatives, decacyclene, and phenoxazone.

[0106] If used, the doping substance is added to thephotocatalyst-containing layer in an amount of 10 to 90% by weight, morepreferably 30 to 70% by weight so that the function of thephotocatalyst-containing layer will not be impaired.

[0107] <Metal Salts>

[0108] The following metal salts are also effective as the substancecapable of improving light emission properties: FeCl₂, FeCl₃, Cr(NO₃)₃,CrCl₃, NaNO₃, Ca(NO₃)₂, Sr(NO₃)₂, Co(NO₃)₂, CoCl₂, Cd(NO₃)₂, Mg(NO₃)₂,Cu(CH₃COO)₂, Cu(NO₃)₂, Ni(NO₃)₂, Mn(NO₃)₂, MnCl₂, PbNO₃, RuCl₃, IrCl₄,Ir(NO₃)₃, ScCl₃, Sc(NO₃)₃, H₂PtCl₆, RhCl₃, Tb(NO₃)₃, Pr(NO₃)₃, Dy(NO₃)₃,Sm(NO₃)₃, Ga(NO₃)₃, Gb(NO₃)₃, Yb(NO₃)₃, NbCl₅, ZrCl₄, Zr(NO₃)₂, KNO₃,LiNO₃, HAsCl₄, Pd(NO₃)₂, Eu(NO₃)₂, Nd(NO₃)₂, NiCl₃, Ce(NO₃)₃, CsNO₃,Er(NO₃)₃, Ba(NO₃)₂, La(NO₃)₃, AgCl, CH₃CH(OH)COOAg, AgNO₃, TlNO₃,Y(NO₃)₃, Pb(NO₃)₂, Ho(NO₃)₃, and Bi(NO₃)₃. It is effective to add themetal salt to the photocatalyst-containing layer in an amount of 0.01 to50% by weight, preferably 0.1 to 10% by weight of the total amount ofthe titanium oxide and the binder in the photocatalyst-containing layer.

[0109] (Other Components for Use in Photocatalyst-Containing Layer)

[0110] Surface-active agents may be added to thephotocatalyst-containing layer for use in the present invention in orderto decrease the wettability of the unexposed part of thephotocatalyst-containing layer. Any surface-active agent is useful aslong as it can be decomposed by the photocatalyst, and removed.Specifically, useful surface-active agents preferably include a seriesof hydrocarbon-based surface-active agents, NIKKOL BL, BC, BO and BBmanufactured by Nihon Surfactant Kogyo K.K., Japan; andfluorine-containing or silicone-based nonionic surface-active agentssuch as ZONYL FSN and FSO manufactured by Du Pont Inc., Surfluon S-141and S-145 manufactured by Asahi Glass Co., Ltd., Japan, Megafac F-141and F-144 manufactured by Dainippon Ink & Chemicals, Inc., Japan,Ftergent F-200 and F-251 manufactured by NEOS Company Limited, Japan,Unidyne DS-401 and DS-402 manufactured by Daikin Industries, Ltd.,Japan, and Fluorad FC-170 and FC-176 manufactured by 3M Corporation. Inaddition, cationic, anionic or ampholytic surface-active agents may alsobe used.

[0111] The photocatalyst-containing layer for use in the presentinvention may contain other components, for example, oligomers orpolymers such as polyvinyl alcohol, unsaturated polyesters, acrylicresins, polyethylene, diallyl phthalate, ethylene-propylene-dienemonomers, epoxy resins, phenolic resins, polyurethane, melamine resins,polycarbonate, polyvinyl chloride, polyamide, polyimide,styrene-butadiene rubber, chloroprene rubber, polypropylene,polybutylene, polystyrene, polyvinyl acetate, nylon, polyesters,polybutadiene, polybenzimidazole, polyacrylonitrile, epichlorohydrin,polysulfide, and polyisoprene.

[0112] The photocatalyst-containing layer for use in the presentinvention may contain sensitizing dyes capable of increasing thephotoactivity of the photocatalyst. When such sensitizing dyes areadded, the photocatalyst-containing layer undergoes change inwettability even when light is applied thereto in a small exposure, orwhen light of a wavelength different from the predetermined one isapplied to the layer.

[0113] (Method of Forming Photocatalyst-Containing Layer)

[0114] The photocatalyst-containing layer can be formed by any method.This layer may be formed by applying a coating liquid containing aphotocatalyst to a substrate by any one of spin coating, spray coating,dip coating, roll coating, bead coating, and the like.

[0115] Any solvent can be used for preparing the coating liquidcontaining a photocatalyst; and an alcoholic organic solvent such asethanol or isopropanol can be used, for instance.

[0116] In the case where the coating liquid contains anultraviolet-curing component as the binder, the formation of thephotocatalyst-containing layer can also be attained by curing treatment,that is, by the application of ultraviolet light.

[0117] (Light for Activating Photocatalyst)

[0118] Any light can be used to activate the photocatalyst as long as itcan excite the photocatalyst. Examples of such light include ultravioletlight, visible light, and infrared light. In addition, electromagneticwaves and radiation whose wavelengths are either shorter or longer thanthat of ultraviolet, visible or infrared light can also be used.

[0119] In the case where anatase titania is used as the photocatalyst,it is possible to excite the photocatalyst by the use of ultravioletlight because anatase titania is excited by light having a wavelength ofnot more than 380 nm. Any of mercury vapor lamps, metal halide lamps,xenon lamps, excimer lasers, and other sources of ultraviolet light canbe used herein as the source of ultraviolet light.

Another Layer of Material whose Wettability Changes when Light IsApplied Thereto

[0120] Besides the above-described photocatalyst-containing layer, apolymeric organic resin layer can be used as the layer of a materialwhose wettability changes when light is applied thereto. The polymerchains of such organic polymers as polycarbonate, polyethylene,polyethylene terephthalate, polyamide and polystyrene are broken whenultraviolet light, especially ultraviolet light chiefly containing raysof shorter wavelengths of 250 nm or less, is applied, and the molecularweights of these polymers are thus decreased. For this reason, whenultraviolet light is applied to the surface of a resin layer made fromone of these polymers, the surface becomes rough, and undergoes changein wettability. As a result, the resin layer becomes highly hydrophilic,that is, compatible with a material to be laminated thereto. Byutilizing this phenomenon, it is possible to create a great differencein wettability between the exposed part and the unexposed part of theresin layer, and to increase the compatibility with the laminatingmaterial. It becomes thus possible to successfully conduct thepatterning of the laminating material.

[0121] EL Layer

[0122] Any El layer can be provided in the EL device of the presentinvention as long as it can cause electroluminescence. The EL layer isprovided on the first electrode (between the first electrode and thesecond electrode); it may be provided on the first electrode eitherdirectly or through the photocatalyst-containing layer or any othernecessary layers.

[0123] The EL layer for use in the present invention comprises aluminous layer as an essential component, and, as optional layers, ahole-transfer layer which serves to transfer holes to the luminouslayer, and an electron-transfer layer which serves to transfer electronsto the luminous layer (these two layers are sometimes collectivelyreferred to as charge-transfer layer). In addition, the EL layer canalso optionally include a hole-injection layer which serves to injectholes to the luminous layer or to the hole-transfer layer, and anelectron-injection layer which serves to inject electrons to theluminous layer or to the electron-transfer layer (these two layers aresometimes collectively referred to as charge-injection layer).

[0124] Materials for forming the above-described constitution layers ofthe EL layer include the following compounds.

[0125] (Luminous layer)

[0126] <Coloring Matter> Cyclopentadiene derivatives,tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazolederivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives,distyrylarylene derivatives, silole derivatives, thiophene cycliccompounds, pyridine cyclic compounds, perynone derivatives, perylenederivatives, oligothiophene derivatives, trifumanylamine derivatives,oxadiazole dimers, and pyrazoline dimers.

[0127] <Metal Complexes> Metal complexes, such as quinolinol aluminumcomplexes, benzoquinolinol beryllium complexes, benzoxazole zinccomplexes, benzothiazole zinc complexes, azomethyl zinc complexes,porphyrin zinc complexes, and europium complexes, having Al, Zn, Be,etc. or rare earth metals such as Tb, Eu and Dy as central metals, andoxadiazole, thiadiazole, phenylpyridine, phenyl benzimidazole andquinoline structures, etc. as ligands.

[0128] <Polymers> Polyparaphenylene vinylene derivatives, polythiophenederivatives, polyparaphenylene derivatives, polysilane derivatives,polyacetylene derivatives, polyvinyl carbazole, and polyfluorenederivatives.

[0129] (Doping Substances)

[0130] Perylene derivatives, coumarin derivatives, rubrene derivatives,quinacridone derivatives, squarium derivatives, porphyrin derivatives,styryl-based colorants, tetracene derivatives, pyrazoline derivatives,decacyclene, and phenoxazone.

[0131] (Hole-Injection Layer (Anode Buffer Materials))

[0132] Phenylamine compounds; star-burst-type amine compounds;phthalocyanine compounds; oxides such as vanadium oxide, molybdenumoxide, rutheniumo xide, and aluminum oxide; amorphous carbon;polyaniline; and polythiophene derivatives.

[0133] (Electron-Injection Layer (Cathode Buffer Materials))

[0134] Lithium aluminate, lithium fluoride, strontium, magnesium oxide,magnesium fluoride, strontium fluoride, potassium fluoride, bariumfluoride, aluminum oxide, strontium oxide, calcium, polymethylmethacrylate, and sodium polystyrenesulfonate.

[0135] (Materials for Partitioning Layer in EL Layer)

[0136] A partitioning layer may be provided in the EL layer. This layeris particularly effective when EL layers that emit light of differentcolors are used in combination. Examples of materials useful for formingthe partitioning layer include photosensitive polyimide resins, acrylicresins, photosetting resins, thermosetting resins, and water-repellentresins.

[0137] First Electrode and Second Electrode

[0138] In this specification, an electrode that is firstly formed iscalled “first electrode”, and an electrode that is formed on the ELlayer is called “second electrode”. There is no particular limitation onthese electrodes. It is however preferable that these electrodes beanode and cathode; in this case, the first electrode may be either anodeor cathode. Either one of anode and cathode is transparent orsemitransparent. If it is transparent, the resulting EL device is adirect-view EL device. If one of the electrodes is made reflective, theresulting EL device is a reflection type EL device.

[0139] It is preferable to use, to make anode, a conductive materialhaving great work function so that holes can easily be injected into theanode, while it is preferable to use, to make cathode, a conductivematerial having low work function so that electrons can easily beinjected into the cathode. Mixtures of a plurality of conductivematerials can also be used to make the electrodes. For both electrodes,it is preferable to use materials having resistances as low as possible.In general, metallic materials are used to make the electrodes; however,organic or inorganic compounds may also be used. Preferred examples ofmaterials for anode include ITO, indium oxide, gold and polyaniline;examples of materials for cathode include magnesium alloys (MgAg, etc.),aluminum alloys (AlLi, AlCa, AlMg, etc.), and metallic calcium.

[0140] To form the first and second electrodes, materials for theelectrodes are deposited through respective electrode pattern masks sothat the two electrodes deposited will have thicknesses between 10 nmand 1 μM and that their patterns will be orthogonal to each other. Whenthe two electrodes are formed in this manner, the resulting EL device isa simple-matrix-addressed EL device. Further, when the electrodes areprovided on a substrate having a thin-film transistor, anactive-matrix-addressed EL device can be obtained.

[0141] Substrate

[0142] In the present invention, the substrate is one on which theelectrodes and the EL layer will be provided, and may be made of atransparent or opaque material. In the EL device of the presentinvention, although the substrate may be the first electrode itself, thefirst electrode is, in general, provided on the surface of the substrateeither directly or through an intermediate layer in order to maintainstrength.

[0143] The substrate may be in the form of plate, film or bulk; and aglass plate, for instance, may be used as the substrate. Any materialcan be used for the substrate as long as it can support the EL device.

[0144] Insulating Layer—in Third Embodiment & Fourth Embodiment

[0145] In a preferred embodiment of the EL device of the presentinvention, at least one insulating layer can partially be formed on thephotocatalyst-containing layer. It is preferable that the insulatinglayer be made from a material containing a photosetting resin such as anultraviolet-curing resin, or a thermosetting resin. This insulatinglayer blocks the supply of charges from the electrode to the EL layer,so that it forms a non-luminous part.

[0146] In the present invention, the use of an ultraviolet-curing resinfor the formation of the insulating layer is advantageous in productionprocess. For example, when, after applying light pattern-wise to thephotocatalyst-containing layer, a material for forming the insulatinglayer is applied only to a part of the photocatalyst-containing layerthat shows increased wettability because of the light applied, and theentire surface is then exposed to ultraviolet light, the insulatinglayer is cured, and, at the same time, a part of thephotocatalyst-containing layer on which the insulating layer is notformed has increased wettability. After this, the EL layer may furtherbe formed on the photocatalyst-containing layer. At this time, the ELlayer may be formed only on the part of the photocatalyst-containinglayer on which the insulating layer is not present (that is, the ELlayer may be formed only on the exposed part of thephotocatalyst-containing layer). Alternatively, the EL layer may beformed on the entire surface of the photocatalyst-containing layer (thatis, the EL layer may be formed on the part of thephotocatalyst-containing layer on which the insulating layer is notpresent, and on the insulating layer formed on thephotocatalyst-containing layer). The selection of a proper manner forthe formation of the EL layer depends on the desired product, productioncost, and the like.

[0147] Production Process

First Embodiment

[0148] According to the present invention, a process for producing an ELdevice in which an EL layer is provided on a photocatalyst-containinglayer comprises the steps of forming a first electrode on a substrate,forming a photocatalyst-containing layer on the first electrode,subjecting the photocatalyst-containing layer to pattern-wise exposureto light to form thereon a latent pattern due to the difference inwettability, applying an EL-layer-forming coating liquid to the exposedpart of the photocatalyst-containing layer to form a patterned EL layer,and forming a second electrode on the EL layer.

[0149] An EL device of the present invention in which a first electrodeis provided on a photocatalyst-containing layer can be produced by aprocess similar to the above one, provided that the process comprisesthe steps of forming, instead of the first electrode, aphotocatalyst-containing layer on the substrate, and applying afirst-electrode-forming coating liquid to the exposed part of thephotocatalyst-containing layer to form a patterned first electrode.

[0150] An EL device of the present invention in which a second electrodeis provided on a photocatalyst-containing layer can be produced by aprocess similar to the above one, provided that the process comprisesthe steps of forming a photocatalyst-containing layer on the EL layerformed on the first electrode, and applying a second-electrode-formingcoating liquid to the exposed part of the photocatalyst-containing layerto form a patterned second electrode.

[0151] Furthermore, those layers other than the photocatalyst-containinglayer and a layer to be formed thereon may be formed by any of processesemployable for producing conventional EL devices.

[0152] Solvents for use in coating liquids that are used for forminglayers on the photocatalyst-containing layer, for example, theEL-layer-forming coating liquid, the first-electrode-forming coatingliquid and the second-electrode-forming coating liquid (collectivelyreferred to as coating liquid) are preferably polar solvents such aswater. Coating liquids prepared by using polar solvents have highwettability against the exposed part of the photocatalyst-containinglayer, but are repelled by the unexposed part of the same. Such coatingliquids are therefore advantageous from the viewpoint of the patterningof the coating liquid layers.

[0153] The coating liquid can be applied to the photocatalyst-containinglayer by such a method as spin coating, ink-jetting, dip coating orblade coating, or by dropping the coating liquid on thephotocatalyst-containing layer.

[0154] The patterning of the EL layer, the first electrode, the secondelectrode, or the like that is formed on the photocatalyst-containinglayer can be effected before the coating liquid applied is notsolidified. Alternatively, the patterning of such a layer can also beeffected, after the coating liquid is solidified to form the layer, bystripping only a part of the layer that has adhered to thelow-wettability part of the photocatalyst-containing layer.Specifically, the patterning of any of the above layers can be effected,for example, by a method in which a substrate coated with the coatingliquid is inclined before the coating liquid is solidified, a method inwhich air is blown, or a method in which an adhesive tape is adhered tothe coating liquid solidified, and then peeled off.

[0155] In the case where the EL device of the present invention is afull-color display, it is preferable to make picture elements on thedisplay so that they correspond to the latent pattern due to thedifference in wettability, formed on the photocatalyst-containing layer.

Second Embodiment

[0156] The method for forming a luminous layer on awettability-changeable material layer includes an ink jet process, aprocess in which a luminous material is applied pattern-wise byprinting, and a vacuum deposition process. In the case of an ink jet orprinting process, the wettability-changeable material layer is exposedto light correspondingly to a pattern that defines the position of aluminous layer of a single color, or luminous layers of R, G and B to beformed. Thereafter, ink of a desired color, or inks of R, G and B areapplied pattern-wise by means of an ink-jetting apparatus or printingmachine. The unexposed part of the wettability-changeable material layerrepels the ink or inks, so that it is possible to accurately adherepattern-wise the ink of each color to the wettability-changeablematerial layer. Thereafter, the conventional procedure for producing anEL device may be employed to obtain an EL device excellent in patternaccuracy.

[0157] Since the exposed part of the wettability-changeable materiallayer has increased wettability, the ink spreads on this part of thelayer uniformly. The film of the ink thus has a thickness improved inevenness.

[0158] In general, a high-molecular-weight material is applied by such acoating method as ink jetting, coating, or pattern printing, while alow-molecular-weight material is applied by vacuum deposition. However,a low-molecular-weight material dispersed in a resin or the like may beapplied by any of the above coating methods to form a film as in theformation of a film of a high-molecular-weight material. Further, ahigh-molecular-weight material may be laminated by vacuum deposition.

[0159] Ink of a single color or inks of the three colors of R, G and Bmay be uniformly applied to the wettability-changeable material layer.In the case of the three colors of R, G and B, a wettability-changeablematerial layer is firstly exposed to light according to a pattern thatdefines the position of a luminous layer of either one of the threecolors to be formed. Thereafter, the wettability-changeable materiallayer is dip-coated with ink of this color. The unexposed part of thewettability-changeable material layer repels the ink, so that theluminous layer of this color can be formed pattern-wise. Next, afteruniformly forming a wettability-changeable material layer on this, thelayer is exposed to light according to a pattern that defines theposition of a luminous layer of a second color to be formed, and theluminous layer of the second color is pattern-wise formed in the samemanner as the above. Lastly, after uniformly forming awettability-changeable material layer on this, the layer is exposed tolight according to a pattern that defines the position of a luminouslayer of a third color to be formed, and the luminous layer of the thirdcolor is pattern-wise formed in the same manner as the above. Thus, theluminous layers of the three colors of R, G and B can be alternatelyformed, and an EL device excellent in pattern accuracy can be obtained.

[0160] A luminous layer of a single color or those of the three colorsof R, G and B may also be formed by homogeneous deposition. This methodutilizes such a fact that a part of the luminous layer that is depositedon the unexposed part of the wettability-changeable material layer caneasily be stripped by the use of an adhesive tape or the like becausethe bonding strength between the exposed part of thewettability-changeable material layer and the luminous layer depositedthereon is high, while the bonding strength between the unexposed partof the same and the luminous layer deposited thereon is low. In the casewhere luminous layers of the three colors of R, G and B are formed bydeposition, these layers can successfully be formed in a manner similarto the above-described uniform coating process, and EL device excellentin pattern accuracy can be obtained.

[0161] To form a luminous layer by an ink-jetting, pattern-printing oruniform coating process, a material for forming the luminous layer inthe form of an aqueous solution, an organic solvent solution, or thelike is used. To form a luminous layer by vacuum deposition, almost alllow-molecular-weight materials can be used althoughhigh-molecular-weight materials may also be used. The thickness of theluminous layer is from 1 nm to 2 μm, preferably from 10 nm to 200 nm.

[0162] Next, the process for producing the first EL device according tothe second embodiment of the present invention will now be described byreferring to FIG. 8. To produce the first EL device, awettability-changeable material layer is, first of all, uniformlylaminated to a patterned electrode 81 by a uniform coating process asshown in FIG. 8 (a). The wettability-changeable material layer is thenexposed to ultraviolet light through a mask having the same pattern asthat of the electrode, or a mask having openings, each having a widththat is the same as or larger than that of the protrusion in thepatterned electrode. A part of the wettability-changeable material layerthat corresponds to the border of the patterned electrode thus becomesan exposed part. It is herein preferable to cover, with an insulatinglayer 89, the edges of the border of the patterned electrode 81 and theparts between the borders of the same in order to prevent short circuitbetween the borders of the patterned electrode 81

[0163] Subsequently, a luminous layer is laminated to thewettability-changeable material layer by an ink-jetting process, or thelike. In the case where the luminous layer is laminated by using acoating liquid, the unexposed part of the wettability-changeablematerial layer repels the coating liquid applied thereto, so that theluminous layer is accurately laminated only to the exposed part of thewettability-changeable material layer that corresponds to the border ofthe patterned electrode. On the other hand, when a luminous layer isformed by vacuum deposition or entire-surface coating, the luminouslayer deposited on the unexposed part can be stripped and removed byusing an adhesive tape or the like. Lastly, although not shown in thisfigure, a counter electrode is formed pattern-wise by deposition so thatthe pattern of this electrode and that of the electrode 81 will beorthogonal to each other. The first EL device can thus be produced.

[0164] By referring to FIG. 9, the process for producing the second ELdevice according to the second embodiment of the present invention willbe described. To produce the second EL device, a wettability-changeablematerial layer is exposed to ultraviolet light through a mask having thenegative pattern of the electrode pattern, or a mask having openings,each having a width smaller than the spacing between the borders of thepatterned electrode as shown in FIG. 9 (b). A part of thewettability-changeable material layer that corresponds to the partbetween the borders of the patterned electrode becomes an exposed part.It is herein preferable to cover, with an insulating layer 99, the edgesof the border of the patterned electrodes 91 and the parts between theborders of the same in order to prevent short circuit between theborders of the patterned electrode 91.

[0165] Subsequently, a partitioning layer is pattern-wise laminated tothe wettability-changeable material layer by an ink-jetting process orthe like. In the case where the partitioning layer is laminated by acoating process, the unexposed part of the wettability-changeablematerial layer repels the material for forming the partitioning layer,so that this material accurately adheres only to the exposed part. Onthe other hand, when the partitioning layer is formed by deposition, itis favorable to use an adhesive tape or the like to strip thepartitioning layer deposited on the unexposed part of thewettability-changeable material layer.

[0166] As shown in FIG. 9 (c), a part of the wettability-changeablematerial layer that corresponds to the border of the patterned electrodeis changed to an exposed part by the application of ultraviolet light. Aluminous layer is then laminated by an ink jet process or the like tothe exposed part of the wettability-changeable material layer, betweenthe borders of the partitioning layer as shown in FIG. 9 (d).

[0167] Lastly, although not shown in this figure, a counter electrode isformed pattern-wise by deposition so that the pattern of this electrodeand that of the electrode 91 will be orthogonal to each other. Thesecond EL device can thus be produced.

[0168] By referring to FIG. 10, the process for producing the thirddevice according to the second embodiment of the present invention willbe described. To produce the third EL device, a wettability-changeablematerial layer 102 is firstly applied to a substrate 106, and anelectrode is then formed pattern-wise on the layer 102 as shown in FIG.10 (a). At this time, it is preferable to apply light, in advance, to apart of the wettability-changeable material layer on which the electrode101 is supposed to be formed. Subsequently, after laminating a luminouslayer to the patterned electrode by an ink jet process or the like asshown in FIG. 10 (b), a part of the wettability-changeable materiallayer that is between the borders of the patterned electrode is changedto an exposed part by the application of light through a mask.Thereafter, a partitioning layer is laminated to the exposed part by anink jet process or the like as shown in FIG. 10 (d). Lastly, althoughnot shown in this figure, a counter electrode is formed pattern-wise bydeposition so that the pattern of this electrode and that of theelectrode 101 will be orthogonal to each other. The third EL device canthus be produced.

Third Embodiment

[0169] The characteristic feature of the process for producing the ELdevice according to the third embodiment of the present invention is asfollows: a latent pattern due to the difference in wettability is formedon a photocatalyst-containing layer by the application of light, and anEL or insulating layer is then formed on the high-wettability part ofthe photocatalyst-containing layer by utilizing this latent pattern,thereby obtaining an EL device capable of displaying, by the emission oflight, a pattern that is different from the electrode pattern.

[0170] A specific embodiment is a process for producing an EL devicethat comprises two facing electrodes and an EL layer provided betweenthem, comprising the steps of forming a photocatalyst-containing layeron one of the electrodes, exposing pattern-wise thephotocatalyst-containing layer to light to form thereon a latent patterndue to the difference in wettability, forming at least one of acharge-injection layer, a charge-transfer layer and a luminous layer onthe exposed part of the photocatalyst-containing layer, and forming theother electrode.

[0171] Another embodiment is a process comprising the steps of forming alatent pattern due to the difference in wettability on aphotocatalyst-containing layer, forming an insulting layer on theexposed part of the photocatalyst-containing layer, forming an EL layeron a part of the photocatalyst-containing layer on which the insulatinglayer is not formed, or on both the photocatalyst-containing layer andthe insulating layer provided thereon after exposing the entire surfaceof the photocatalyst-containing layer to light, and forming the otherelectrode.

[0172] A further embodiment is a process comprising the steps of forminga latent pattern due to the difference in wettability on aphotocatalyst-containing layer, forming an insulating layer on theexposed part of the photocatalyst-containing layer by the use of anultraviolet-curing resin, applying ultraviolet light to the entiresurface of the photocatalyst-containing layer provided with theinsulating layer, forming at least one of a charge-injection layer, acharge-transfer layer and a luminous layer, and forming the otherelectrode.

[0173] To form the EL layer or insulating resin layer on the latentpattern formed on the photocatalyst-containing layer in theabove-described processes, a material for forming the EL layer or theinsulating resin layer may be adhered pattern-wise to thephotocatalyst-containing layer by ink jetting or vacuum deposition.Typically, in this case, patterning is conducted upon the application ofthe material to the photocatalyst-containing layer. It is however alsopossible to adopt, if desired, such a manner that a pattern is formed byremoving a part of the coating liquid layer that is on thelow-wettability part of the photocatalyst-containing layer, by applyingphysical or chemical energy to the photocatalyst-containing layer eitherafter or before its solidification. To effect the above removal,stripping by the use of an adhesive tape, or etching may be useful.

[0174] Typically, the above-described processes are employed to producethe EL devices of the present invention. It is however acceptable toproduce them by a process different from the above ones. Moreover, an ELdevice having a structure that can be attained only by a processdifferent from the above-described ones is also acceptable. For example,other layers may be laminated between the electrode and thephotocatalyst-containing layer.

Fourth Embodiment

[0175] An EL device of the present invention in which aphotocatalyst-containing layer is provided between a plurality of ELlayers can be produced by a process similar to that for producing the ELdevice of the first embodiment, provided that the process comprises thesteps of forming a photocatalyst-containing layer not on the firstelectrode but on a first EL layer, and applying asecond-EL-layer-forming coating liquid to the exposed part of thephotocatalyst-containing layer to form pattern-wise a second EL layerand that the photocatalyst-containing layer contains a substance capableof improving light emission properties.

[0176] An EL device of the present invention in which an insulatinglayer is provided on a photocatalyst-containing layer can be produced bya process similar to that for producing the EL device of the firstembodiment, provided that the process comprises the step of applying aninsulating-layer-forming coating liquid to the exposed part of thephotocatalyst-containing layer, and curing the coating liquid by drying,heating or applying light to from pattern-wise an insulating layer onthe photocatalyst-containing layer and that the photocatalyst-containinglayer contains a substance capable of improving light emissionproperties.

[0177] There can also be obtained other devices by processes similar tothat for producing the EL device of the first embodiment, provided thata substance capable of improving light emission properties isincorporated into the photocatalyst-containing layer.

[0178] Effects

[0179] The present invention provides an EL device that can simply beproduced and a process for producing the EL device.

[0180] The EL device of the present invention contains a luminous layerexcellent in pattern accuracy, shows excellent displaying properties,and is free from continuity across the electrodes.

[0181] Furthermore, the present invention provides a simple process forproducing an EL device capable of displaying a pattern by the emissionof light, and an EL device that can be produced through the process.

[0182] In addition, the present invention provides an EL device havingexcellent light emission properties, characterized in that thepatterning of its constituent layers can easily be made, and a processfor producing such an EL device.

EXAMPLES

[0183] The present invention will now be explained more specifically byreferring to the following Examples. Examples A, B, C and D correspondto the first, second, third and fourth embodiments of the presentinvention, respectively.

Example A-1-1

[0184] A photocatalyst-containing-layer-forming coating liquid and anEL-layer-forming coating liquid having the following compositions wererespectively prepared.

[0185] (Photocatalyst-Containing-Layer-Forming Coating Liquid A-1)Anatase Titania Sol (ST-K03 manufactured 6 parts by weight by IshiharaSangyo Kaisha, Ltd., Japan) Fluoroalkoxysilane (MF-160E manufactured1.26 parts by weight by TOHKEM PRODUCTS CORPORATION, Japan) 1NHydrochloric acid 12 parts by weight Isopropyl alcohol 58.5 parts byweight

[0186] The above-prepared photocatalyst-containing-layer-forming coatingliquid was applied to a cleaned glass substrate by means of a spincoater, and dried at 150° C. for 10 minutes to carry out hydrolysis andpolycondensation reaction, thereby forming a 20-nm thick transparentphotocatalyst-containing layer in which the photocatalyst was firmlyfixed in the organosiloxane.

[0187] Light (wavelength: 365 nm) emitted from a mercury vapor lamp wasapplied, through a mask, to the photocatalyst-containing layer with anillumination intensity of 70 mW/cm² for 50 seconds. The contact angelwith water of the exposed part of the photocatalyst-containing layer andthat of the unexposed part of the same were measured by the use of acontact angle meter (CA-Z type, manufactured by Kyowa Interface ScienceCo. LTD, Japan). The measurement was carried out 30 seconds after waterwas dropped from a micro-syringe to the surface of thephotocatalyst-containing layer. The results were as follows: the contactangle with water of the unexposed part was 142°, while that of theexposed part was not more than 10°. It was thus confirmed that it waspossible to form, on the photocatalyst-containing layer, a latentpattern due to the difference in wettability between the exposed partand the unexposed part.

[0188] (EL-Layer-Forming Coating Liquid A-1) Polyvinyl carbazole (Lot.K81127 manufactured 70 parts by weight by Anan Corporation, Japan)Oxadiazole compound (manufactured 30 parts by weight by Wako PureChemical Industries, Inc., Japan) Coumarin 6 (manufactured by 1 part byweight Aldrich Chemical Corporation) 1,2-Dichloroethane (manufactured by3367 part by weight Junsei Chemical Co., Ltd., Japan)

[0189] To an ITO glass substrate provided with a line pattern with aline spacing of 24 μm and a line width of 162 μm, a positive-type resist(ZPP-1850 manufactured by Nippon Zeon Co., Ltd., Japan) was applied bymeans of a spin coater to a thickness of 1 μm, and dried at 110° C. for90 seconds. Thereafter, 150 mJ of light having a wavelength of 365 nmwas applied only to a part of the resist film that was between theborders of the line pattern on the ITO, and the exposed resist wasdeveloped by using an organic amine developer. The resist developed wasbaked at 130° C. for 10 minutes to form an insulating layer on the ITOsubstrate between the borders of the line pattern thereon. Theabove-prepared photocatalyst-containing-layer-forming coating liquid A-1was applied to the entire surface of this ITO substrate by means of aspin coater, and then dried at 150° C. for 10 minutes to carry outhydrolysis and polycondensation reactions, thereby forming a100-angstrom thick transparent photocatalyst-containing layer in whichthe photocatalyst was firmly fixed in the organosiloxane. Subsequently,light (wavelength: 365 nm) emitted from a mercury vapor lamp wasapplied, through a mask, to the photocatalyst-containing layer with anillumination intensity of 70 mW/cm² for 50 seconds. Thus, only a part(width: 170μm; 4 μm wider, on both the right and left sides, than theline width of the line pattern on the ITO) of thephotocatalyst-containing layer that corresponded to the border of theline pattern on the ITO substrate was exposed to the light.

[0190] Next, poly(3,4)ethylenedioxythiophene/polystyrenesulfon ate(abbreviation: PEDOT/PSS, trade name: Baytron PTP AI 4083, product ofBayer A.G.) was applied with a spin coater to the entire surface of thephotocatalyst-containing layer that had been subjected to pattern-wiseexposure, and dried at 130° C. A PEDOT film having a thickness ofapproximately 1000 angstroms was thus formed only on the exposed part ofphotocatalyst-containing layer that corresponded to the border of theline pattern on the ITO. To the entire surface of this, theabove-described EL-layer-forming coating liquid A-1 was further appliedwith a spin coater. Lastly, as an upper electrode, a 5-angstrom thickLiF film and a 2000-angstrom thick aluminum film were respectivelydeposited pattern-wise by using the same mask so that the pattern ofthis electrode and those of the ITO and of the organic EL layer would beorthogonal to each other. When the EL device thus obtained was driven bythe use of the ITO electrode and the Al upper electrode as addresselectrodes, it emitted light of green color.

Example A-1-2

[0191] The procedure of Example A-1-1 was repeated, provided that thethickness of the photocatalyst-containing layer was decreased to 2000angstroms by decreasing the amount (parts by weight) of the isopropylalcohol used as a solvent for preparing thephotocatalyst-containing-layer-forming coating liquid A-1. The EL devicethus obtained emitted light of green color.

Example A-1-3

[0192] The procedure of Example A-1-1 was repeated, provided that thePEDOT layer was not provided. The EL device thus obtained emitted lightof green color.

Example A-1-4

[0193] The procedure of Example A-1-2 was repeated, provided that thePEDOT layer was not provided. The EL device thus obtained emitted lightof green color.

Example A-1-5

[0194] The procedure of Example A-1-3 was repeated, provided that thephotocatalyst-containing-layer-forming coating liquid A-1 used inExample A-1-3 was replaced with a photocatalyst-containing-layer-formingcoating liquid A-2 having the composition below described. The EL devicethus obtained emitted light of green color.

[0195] (Photocatalyst-Containing-Layer-Forming Coating Liquid A-2)Photocatalyst inorganic coating agent 2 parts by weight (ST-K03manufactured by Ishihara Sangyo Kaisha, Ltd., Japan) Fluoroalkoxysilane(MF-160E manufactured 0.001 parts by weight by TOHKEM PRODUCTSCORPORATION, Japan) 2N Hydrochloric acid 4 parts by weight Isopropylalcohol 7.5 parts by weight

Example B-1-1

[0196] The procedure of Example A-1-3 was repeated, provided that theorganic- EL-layer-forming coating liquid used in Example A-1-3 wasreplaced with the following coating liquids:

[0197] a coating liquid for forming a luminous layer of green color: thesame as the organic-EL-layer-forming coating liquid in Example A-1-3;

[0198] a coating liquid for forming a luminous layer of red color:having the same composition as that of the organic-EL-layer-formingcoating liquid in Example A-1-3 except that the coumarin was replacedwith Nile Read; and

[0199] a coating liquid for forming a luminous layer of blue color:having the same composition as that of the organic-EL-layer-formingcoating liquid in Example A-1-3 except that the coumarin was replacedwith perylene.

[0200] The structural formula of Nile Red is as follows:

[0201] The structural formula of perylene is as follows:

[0202] Light was applied only to a part of the photocatalyst-containinglayer to which the above-described coating liquids of the three colorswere supposed to be applied. The coating liquids were then applied tothe exposed part of the photocatalyst-containing layer in the samemanner as in Example A-1-3, using an ink-jetting apparatus. Namely, on apart of the photocatalyst-containing layer that corresponded to theborder of the patterned electrode on the ITO substrate provided with theinsulating layer, the coating liquids were alternately applied, anddried at 80° C. for 30 minutes. A 100-nm thick luminous layer composedof sections of the three colors was thus formed only on the exposed partof the photocatalyst-containing layer.

[0203] A 150-nm thick AlLi alloy film was deposited as an upperelectrode by using a mask so that the pattern of this electrode andthose of the ITO electrode and of the organic EL layer would beorthogonal to each other, thereby obtaining a tricolorsimple-matrix-addressed EL device.

[0204] When this EL device was driven by the use of the ITO electrodeand the AlLi upper alloy electrode as address electrodes, it wasconfirmed to have excellent displaying performance.

Example B-1-2

[0205] The procedure of Example B-1-1 was repeated, provided that thecoating liquids were alternately applied not by the ink-jettingapparatus used in Example B-1-1 but by a gravure-printing machine.

[0206] When this tricolor simple-matrix-addressed EL device thusobtained was driven by the use of the ITO electrode and the AlLi upperalloy electrode as address electrodes, it was confirmed to haveexcellent displaying performance.

Example B-1-3

[0207] After cleaning an ITO substrate provided with a line pattern witha height of 0.15 μm, a line width of 200 μm and a line spacing of 200μm, a 20-nm thick photocatalyst-containing layer was formed on theentire surface of this ITO substrate in the same manner as in ExampleB-1-1. Subsequently, light (wavelength: 365 nm) emitted from a mercuryvapor lamp was applied through a mask with an illumination intensity of70 mW/cm² for 50 seconds only to a part of the photocatalyst-containinglayer that corresponded to the part between the borders of the patternedITO electrode.

[0208] To this was then applied, with a dip coater, anultraviolet-curing resin solution consisting of an ultraviolet-curingresin (PEG400DA manufactured by Nippon Kayaku Co., Ltd., Japan) and aninitiator (Darocur 1173 available from Ciba Specialty Chemicals K.K.,Japan) in an amount of 5% by weight of the ultraviolet-curing resin. Theultraviolet-curing resin solution adhered only to the exposed part ofthe photocatalyst-containing layer that corresponded to the part betweenthe borders of the patterned ITO electrode.

[0209] To the entire surface of this, light (wavelength: 365 nm) emittedfrom a mercury vapor lamp was applied with an illumination intensity of70 mW/cm² for 50 seconds to cure the ultraviolet-curing resin to form a0.2-μm thick partitioning layer with a spacing of 200 μm. At the sametime, the wettability of a part of the photocatalyst-containing layerthat corresponded to the border of the patterned ITO electrode wasincreased to a contact angle with water of approximately 0°.

[0210] Thereafter, the organic-EL-layer-forming coating liquids ofgreen, red and blue used in Example B-1-1 were alternately applied tothe exposed part of the photocatalyst-containing layer that correspondedto the border of the patterned ITO electrode by the use of anink-jetting apparatus, and then dried at 80° C. An organic El layerhaving a thickness of 100 nm was thus formed between the borders of thepatterned partitioning layer.

[0211] An AlLi alloy film was deposited as an upper electrode by using amask so that the thickness, line width and line spacing of the resultingpatterned film would be 150 nm, 200 μm and 200 μm, respectively and thatthe pattern of this film and those of the ITO electrode and of theorganic EL layer would be orthogonal to each other, thereby obtaining atricolor simple- matrix-addressed EL device.

[0212] When this EL device was driven by the use of the ITO electrodeand the AlLi alloy upper electrode as address electrodes, it wasconfirmed to have excellent displaying performance.

Example B-1-4

[0213] A cleaned glass substrate was spin-coated with thephotocatalyst-containing-layer-forming coating liquid described inExample B-1-1. The coating liquid was then dried at 150° C. for 10minutes to carry out hydrolysis and polycondensation reaction, therebyforming a 20-nm thick transparent photocatalyst-containing layer inwhich the photocatalyst was firmly fixed in the organosiloxane. To thisphotocatalyst-containing layer, light (wavelength: 365 nm) emitted froma mercury vapor lamp was applied with an illumination intensity of 70mW/cm² for 50 seconds through a mask having a line pattern with a linewidth of 200 μm and a line spacing of 200 μm. ITO was then sputtered sothat a 0.15-μm thick ITO film would be formed only on the exposed partof the photocatalyst-containing layer.

[0214] To this was then applied, by means of a bead coater, theorganic-EL-layer-forming coating liquid used in Example B-1-1. As aresult, the organic-EL-layer-forming coating liquid adhered only to theITO layer. This coating liquid was then dried in an oven at 80° for 30minutes to obtain a patterned organic EL layer having a thickness of 100nm.

[0215] Only to a part of the photocatalyst-containing layer on which theorganic EL layer had not been formed, light (wavelength: 365 nm) emittedfrom a mercury vapor lamp was applied from the organic EL layer sidewith an illumination intensity of 70 mW/cm² for 50 seconds through amask having a line pattern with a line width of 200 μm. To the exposedpart of the photocatalyst-containing layer was then applied theultraviolet-curing resin solution described in Example B-1-5 by means ofan ink-jetting apparatus. Thereafter, light (wavelength: 365 nm) emittedfrom a mercury vapor lamp was applied, through a mask, only to theultraviolet-curing resin solution applied with an illumination intensityof 70 mW/cm² for 50 seconds, thereby providing a partitioning layerhaving a thickness of 0.2 μm.

[0216] An AlLi alloy film was deposited as an upper electrode by usingthe same mask as in Example B-1-1 so that the thickness, line width andline spacing of the resulting film would be 150 nm, 200 μm and 200 μm,respectively and that the pattern of this film and those of the ITOelectrode and of the organic EL layer would be orthogonal to each other,thereby obtaining a mono-color simple-matrix-addressed EL device.

[0217] When this EL device was driven by the use of the ITO electrodeand the AlLi alloy upper electrode as address electrodes, it wasconfirmed to have excellent displaying performance.

Example B-1-5

[0218] The procedure of Example B-1-4 was repeated, provided that thecoating liquid for forming an organic EL layer of a single color used inExample B-1-4 was replaced with the coating liquids for forming luminouslayers of the three colors of green, red and blue described in ExampleB-1-1 and that these coating liquids were alternately applied by the useof an ink-jetting apparatus. The EL device obtained was a tricolorsimple-matrix-addressed EL device excellent in displaying performance.

Example B-2-1

[0219] The procedure of Example B-1-1 was repeated to obtain an ELdevice, provided that the thickness of the photocatalyst-containinglayer was changed to 50 angstroms. A three-colored line patternoriginating from the luminous layers of the three colors did not appearon the EL device obtained.

Example B-2-2

[0220] The procedure of Example B-1-1 was repeated to obtain an ELdevice, provided that the thickness of the photocatalyst-containinglayer was changed to 3000 angstroms. The EL device obtained did not emitlight at all.

Example B-2-3

[0221] The procedure of Example B-1-1 was repeated to obtain an ELdevice, provided that the photocatalyst-containing layer was notprovided. A three-colored line pattern originating from the luminouslayers of the three colors did not appear on the EL device obtained.

Example B-2-4

[0222] The procedure of Example B-1-1 was repeated to obtain an ELdevice, provided that a PEDOT layer was provided instead of thephotocatalyst-containing layer. A three-colored line pattern originatingfrom the luminous layers of the three colors did not appear on the ELdevice obtained.

Example C-1-1

[0223] (Preparation of Photocatalyst-Containing-Layer-Forming CoatingLiquid)

[0224] A photocatalyst-containing-layer-forming coating liquid havingthe following composition was firstly prepared. Photocatalyst inorganiccoating agent 6 parts by weight (ST-K03 manufactured by Ishihara SangyoKaisha, Ltd., Japan) Fluoroalkoxysilane (MF-160E manufactured 1.26 partsby weight by TOHKEM PRODUCTS CORPORATION, Japan) 1N Hydrochloric acid 12parts by weight Isopropyl alcohol 58.5 parts by weight

[0225] The above-prepared photocatalyst-containing-layer-forming coatingliquid was applied to a cleaned glass substrate by means of a spincoater, and dried at 150° C. for 10 minutes to carry out hydrolysis andpolycondensation reaction, thereby forming a 20-nm thick transparentphotocatalyst-containing layer in which the photocatalyst was firmlyfixed in the organosiloxane.

[0226] (Formation of Latent Pattern due to Difference in Wettability onPhotocatalyst-Containing Layer)

[0227] Light (wavelength: 365 nm) emitted from a mercury vapor lamp wasapplied through a mask to the photocatalyst-containing layer with anillumination intensity of 70 mW/cm² for 50 seconds. The contact angelwith water of the exposed part of the photocatalyst-containing layer andthat of the unexposed part of the same were measured by the use of acontact angle meter (CA-Z type, manufactured by Kyowa Interface ScienceCo. LTD, Japan). The measurement was carried out 30 seconds after waterwas dropped from a micro-syringe to the surface of thephotocatalyst-containing layer. The results were as follows: the contactangle with water of the unexposed part was 142°, while that of theexposed part was not more than 10°. It was thus confirmed that it waspossible to form, on the photocatalyst-containing layer, a latentpattern due to the difference in wettability between the exposed partand the unexposed part.

[0228] (Preparation of Luminous-Layer-Forming Coating Liquid)

[0229] A coating liquid having the following composition was prepared toform a luminous layer for an organic EL device. Polyvinyl carbazole 70parts by weight Coumarin 6 1 part by weight Oxadiazole compound 30 partsby weight 1,1,2-Trichloroethane 663 part by weight

[0230] (Production of Organic EL device)

[0231] After cleaning an ITO substrate, the above-describedphotocatalyst-containing layer having a thickness of 20 nm was formed onthe entire surface of the substrate. Subsequently, light (wavelength:365 nm) emitted from a mercury vapor lamp was applied to thephotocatalyst-containing layer with an illumination intensity of 70mW/cm² for 50 seconds through a mask having 5-mm square openings.

[0232] Next, when the organic-EL-layer-forming coating liquid wasapplied to the entire surface of the above photocatalyst-containinglayer by the use of a spin coater, the coating liquid adhered only tothe 5-mm square exposed parts of the photocatalyst-containing layer.This coating liquid was dried at 80° C. to form a luminous layer havinga thickness of 100 nm only on the exposed part of thephotocatalyst-containing layer.

[0233] On the entire surface of this, a 500-nm thick AlLi alloy film wasdeposited as an upper electrode to obtain an EL device. The EL devicecaused pattern-wise emission of light.

Example C-1-2

[0234] Like in Example C-1-1, after cleaning an ITO substrate, theabove-described photocatalyst-containing layer having a thickness of 200nm was formed on the entire surface of the substrate. Subsequently,light (wavelength: 365 nm) emitted from a mercury vapor lamp was appliedto the photocatalyst-containing layer with an illumination intensity of70 mW/cm² for 50 seconds through a mask having 5-mm square openings.Thereafter, the photocatalyst-containing layer was spin-coated with acommercially available conductive coating liquid (PEDOT manufactured byBayer A.G.) as a hole-injection-layer-forming coating liquid. As aresult, the coating liquid adhered only to the 5-mm square exposed partsof the photocatalyst-containing layer. This coating liquid was thenheated at 80° C. for 30 minutes to form a 50-nm thick hole-injectionlayer in a 5-mm square pattern. To the entire surface of this, theluminous-layer-forming coating liquid described in Example C-1-1 wasapplied, and dried at 80° C., whereby a luminous layer having athickness of 100 nm was formed on the entire surface.

[0235] On top of the entire surface of this, a 50-nm thick AlLi alloyfilm was deposited as an upper electrode to obtain an EL device. The ELcaused pattern-wise emission of light.

Example C-1-3

[0236] After cleaning an ITO substrate, the above-describedphotocatalyst-containing layer having a thickness of 200 nm was formedon the entire surface of the substrate. Subsequently, while masking 5-mmsquare parts of the photocatalyst-containing layer, light (wavelength:365 nm) emitted from a mercury vapor lamp was applied with anillumination intensity of 70 mW/cm² for 50 seconds. To this was thenapplied, with a spinner, an ultraviolet-curing resin solution consistingof a commercially available ultraviolet-curing resin (trade namePEG400DA, manufactured by Nippon Kayaku Co., Ltd., Japan) and aninitiator (trade name Darocure 1173, available from Ciba SpecialtyChemicals K.K., Japan) in an amount of 5% by weight of theultraviolet-curing resin. As a result, the ultraviolet-curing resinsolution adhered only to a part of the photocatalyst-containing layerother than the 5-mm square parts. Thereafter, to the entire surface ofthis, light (wavelength: 365 nm) emitted from a mercury vapor lamp wasapplied with an illumination intensity of 70 mW/cm² for 50 seconds tocure the ultraviolet-curing resin, and, at the same time, to increasethe wettability of the 5-mm square parts of the photocatalyst-containinglayer. To this, the luminous-layer-forming coating liquid described inExample C-1-1 was entirely applied, and dried at 80° C. to form aluminous layer. On the entire surface of the luminous layer, a 500-nmthick AlLi alloy film was deposited as an upper electrode to obtain anEL device. This EL device caused pattern-wise emission of light.

Example D-1-1

[0237] A coating liquid having the following composition was prepared.

[0238] (Coating Liquid D-1: Photocatalyst-Containing-Layer-FormingCoating Liquid) Photocatalyst inorganic coating agent 6 parts by weight(ST-K03 manufactured by Ishihara Sangyo Kaisha, Ltd., Japan)Fluoroalkoxysilane (MF-160E manufactured 1.26 parts by weight by TOHKEMPRODUCTS CORPORATION, Japan) 1N Hydrochloric acid 12 parts by weightIsopropyl alcohol 58.5 parts by weight

[0239] The above ingredients were mixed one after another, and themixture was stirred at 100° C. for 20 minutes, and then diluted with 10parts by weight of isopropyl alcohol to obtain coating liquid D-1 (theabove photocatalyst is called “DSR” for short).

[0240] (Coating Liquids D-2 and D-3: Coating Liquids for FormingPhotocatalyst-Containing Layer Containing Substance Capable of ImprovingLight Emission Properties)

[0241] The above-prepared coating liquid D-1 and an aqueous dispersionof poly-3,4-ethylenedioxy thiophene/polystyrenesulfonate (abbreviation:PEDOT/PSS, trade name: Baytron PT PAI4083, product of Bayer A.G.) weremixed at the weight ratios of 2:1 and 1:2 to obtain coating liquids D-2and D-3, respectively.

[0242] (Coating Liquids D-4, D-5 and D-6)

[0243] 0.0324 g of FeCl₃was dissolved in 20 g of isopropyl alcohol, and0.157 g of this solution and 4 g of the above coating liquid D-1 weremixed to obtain coating liquid D-4.

[0244] The same procedure was repeated except that 0.0324 g of FeCl₃ wasreplaced with 0.0483 g of copper (III) nitrate trihydrate, therebyobtaining liquid D-5.

[0245] The same procedure was repeated except that 0.0324 g of FeCl₃ wasreplaced with 0.056 g of manganese (II) nitrate hexahydrate, therebyobtaining liquid D-6.

[0246] (Coating Liquid D-7: EL-Layer-Forming Coating Liquid)Polyfluorene derivative 1 part by weight Xylene 66.67 parts by weight

[0247] The above polyfluorene derivative was synthesized in thefollowing manner.

[0248] In the stream of dry nitrogen, 5.0 g (30 mmol) of fluorene wasdissolved in dry tetrahydrofuran. To this solution, 22 m l (35 mmol) ofa 1.6 M hexane solution of n-butylithium was added dropwise at −78° C.,and the mixture was stirred at the temperature for 1 hour. To this wasthen added dropwise 4.9 ml (35 mmol) of n-hexyl bromide, and the mixturewas stirred at −78° C. for 1 hour, and then at room temperature for 1hour. To the resultant, 22 ml (35 mmol) of a 1.6 M hexane solution ofn-butylithium was further added dropwise at −78° C., and the mixture wasstirred at the temperature for 1 hour. To this was then added dropwise4.9 ml (35 mmol) of n-hexyl bromide, and the mixture was stirred at −78°C. for 1 hour, and then at room temperature for 1 hour. Water was addeddropwise to this mixture with ice-cooling, and the resultant was thensubjected to extraction with ethyl acetate. The extract was dehydratedand dried over magnesium sulfate, and the solvent was then distilledoff. The residue was subjected to recrystallization from hexane toobtain 9.5 g (95%) of 9,9-dihexylfluorene.

[0249] 2.0 g (6.0 mmol) of the 9,9-dihexylfluorene and 0.02 g (0.12mmol) of iron chloride (III) were dissolved in 9 ml of chloroform. Whileshading the light, 1.2 g of bromine dissolved in 3 ml of chloroform wasadded dropwise to the above solution with stirring at 0° C. This mixturewas stirred at room temperature for 18 hours, washed with an aqueoussodium thiosulfate solution, and dehydrated and dried over magnesiumsulfate. The solvent was then distilled off. The residue was purified bycolumn chromatography (eluent: hexane) to isolate 2.4 g (92%) of2,7-dibromo-9,9-dihexylfuorene.

[0250] In the stream of dry nitrogen, 2.0 g (40 mmol) of the2,7-dibromo-9,9-dihexylfluorene was dissolved in 40 ml of drytetrahydrofuran. To this solution, 5.3 ml (8.4 mmol) of a 1.6 M hexanesolution of n-butylithium was added dropwise with ice-cooling, and themixture was stirred at 0° C. for 1 hour. To this was then added dropwise2.0 ml (10 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborane,and the mixture was stirred at 0° C. for 1 hour, and then at roomtemperature for 12 hours. Water was added dropwise to this mixture withice-cooling, and the resultant was subjected to extraction with diethylether. The extract was dehydrated and dried over magnesium sulfate, andthe solvent was distilled off. After washing with ethanol, the residuewas subjected to recrystallization from an ethanol/hexane solventmixture to obtain 1.4 g (60%) of2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-yl)-9,9-dihexylfluorene.

[0251] In the stream of dry nitrogen, 0.53 g of the2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-yl)-9,9-dihexylfluorene,0.45 g of the 2,7-dibromo-9,9-dihexylfluorene, and 0.02 g oftetrakis(trisphenylphosphine)-paradium were dissolved in 18 ml of drytoluene. To this solution was added 27 ml of a 2 M aqueous sodiumcarbonate solution, and the mixture was stirred at 100° C. for 48 hourswith heating. After cooling, this mixture was poured into methanol. Theprecipitates were washed with a dilute aqueous hydrochloric acidsolution. By using a Soxhlet apparatus, and acetone as a solvent, thenonvolatile matter was extracted from the precipitates. The residue wasdissolved in chloroform, and the solution was subjected toreprecipitation to obtain the desired polyfluorene derivative.

[0252] An ITO glass substrate was subjected to patterning to form a12-mm wide strip on its central part. After cleaning andsurface-treating this glass substrate, the above-described coatingliquid D-1, D-2, D-3, D-4, D-5 or D-6 was applied to the substrate witha spin coater, and dried and baked in a clean oven at 150° C. for 10minutes to form a thin film having a thickness of 50 nm. Subsequently,light (dominant wavelength: 365 nm) emitted from a high pressuremercury-vapor lamp was applied to this thin film of coating liquid D-1,D-2, D-3, D-4, D-5 or D-6 in an exposure of 5000 mJ. To each exposedthin film, the above-prepared coating liquid D-7 was applied by means ofa spin coater to form a thin film having a thickness of 100 nm. Lastly,a 0.5-nm thick LiF film and a 150-nm thick aluminum film wererespectively deposited as an upper electrode by using a mask so that thepattern of these films and that of the ITO would be orthogonal to eachother. The EL devices respectively obtained in this manner were drivenby the use of the Al upper electrode and the ITO electrode as addresselectrodes. As a result, the EL devices were observed to emit light.

[0253] The light emission properties of these EL devices were examined.As a result, the relationships between luminance and voltage as shown inFIG. 11 were obtained. The EL device in which thephotocatalyst-containing layer was not provided is herein referred to asEL device D-0. Coating liquids D-4, D-5 and D-6 are similar to coatingliquid D-3, so that the data regarding the EL devices whosephotocatalyst-containing layers were formed by using coating liquidsD-3, D-4, D-5 and D-6 (hereinafter referred to as EL devices D-3, D-4,D-5 and D-6, respectively) are plotted collectively.

[0254] As shown in FIG. 11, the EL devices provided withphotocatalyst-containing layers are driven at low applied voltages, andhave high luminous efficiencies as compared with EL device D-0 providedwith no photocatalyst-containing layer. Both the EL device whosephotocatalyst-containing layer was formed by using coating liquid D-2(hereinafter referred to as EL device D-2) and EL device D-3 contain asubstance capable of improving light emission properties in theirphotocatalyst-containing layers. Although these two EL devices haveslightly decreased luminous efficiencies, they are driven at low appliedvoltages, and have high luminances as compared with the EL device whosephotocatalyst-containing layer was formed by using coating liquid D-1(hereinafter referred to as EL device D-1).

[0255] Furthermore, the data shown in the following table demonstratethat EL devices D-4, D-5 and D-6, each having a photocatalyst-containinglayer that contains a substance capable of improving light emissionproperties, have high luminous efficiencies as compared with EL deviceD-1. Luminous Efficiency (cd/A) EL Device D-0 0.35 EL Device D-1 1.05 ELDevice D-2 0.70 EL Device D-3 0.62 EL Device D-4 1.46 EL Device D-5 1.33EL Device D-6 1.44

1. An EL device comprising: a first electrode, an EL layer formed on thefirst electrode, and a second electrode formed on the EL layer, whereinat least one layer of a material whose wettability changes when light isapplied thereto is formed.
 2. The EL device according to claim 1 ,wherein the first electrode is formed on a substrate, and the layer of amaterial whose wettability changes when light is applied thereto is aphotocatalyst-containing layer, at least one photocatalyst-containinglayer being formed at any position between the substrate and the secondelectrode.
 3. The EL device according to claim 2 , wherein thephotocatalyst-containing layer has a thickness of 50 to 2000 angstroms.4. The EL device according to claim 2 , wherein thephotocatalyst-containing layer is formed between the first electrode andthe EL layer.
 5. A full-color display comprising the EL device set forthin claim 1 .
 6. The EL device according to claim 1 , wherein the firstelectrode is formed pattern-wise, the EL layer contains at least aluminous layer that is formed correspondingly to the pattern of thefirst electrode, and the second electrode is formed pattern-wise on theluminous layer, the luminous layer being formed by utilizing thedifference in wettability between the exposed part and the unexposedpart of the layer of a material whose wettability changes when light isapplied thereto.
 7. The EL device according to claim 6 , wherein the ELlayer is composed of a plurality of luminous layers formed on the firstelectrode correspondingly to the pattern of the first electrode, andpartitioning layers formed between the borders of the patterned luminouslayers, at least one of the luminous layers and partitioning layersbeing formed by utilizing the difference in wettability between theexposed part and the unexposed part of the layer of a material whosewettability changes when light is applied thereto.
 8. The EL deviceaccording to claim 6 , wherein the luminous layer is formed on theelectrode through at least one of a buffer layer and a charge-transferlayer.
 9. The EL device according to claim 6 , wherein the exposed partof the layer of a material whose wettability changes when light isapplied thereto is highly hydrophilic, and the unexposed part of thesame is water-repellent.
 10. The EL device according to claim 6 ,wherein the layer of a material whose wettability changes when light isapplied thereto is a photocatalyst-containing layer that contains atleast a photocatalyst and a binder.
 11. The EL device according to claim10 , wherein the photocatalyst contained in the photocatalyst-containinglayer is titanium dioxide.
 12. The EL device according to claim 10 ,wherein the binder contained in the photocatalyst-containing layer is anorganopolysiloxane obtained by hydrolyzing and polycondensingchlorosilane or an alkoxysilane.
 13. The EL device according to claim 10, wherein the binder contained in the photocatalyst-containing layer isan organopolysiloxane obtained by crosslinking a reactive silicone. 14.The EL device according to claim 1 , wherein the layer of a materialwhose wettability changes when light is applied thereto comprises apolymeric organic resin.
 15. The EL device according to claim 1 ,wherein the layer of a material whose wettability changes when light isapplied thereto is a photocatalyst-containing layer, and the EL devicecan display, by the emission of light, a pattern that is different fromeither the pattern of the first electrode or that of the secondelectrode.
 16. The EL device according to claim 15 , comprising at leastone patterned buffer layer, charge-injection layer, charge-transferlayer or luminous layer on the photocatalyst-containing layer, capableof displaying, by the emission of light, a pattern corresponding to thepattern of the buffer, charge-injection, charge-transfer or luminouslayer.
 17. The EL device according to claim 15 , in which either thefirst electrode or the second electrode is anode, which comprises thephotocatalyst-containing layer formed on the anode, a patternedhole-injection layer formed on the photocatalyst-containing layer, and aluminous layer formed on the hole-injection layer, and which candisplay, by the emission of light, a pattern corresponding to thepattern of the hole-injection layer.
 18. The EL device according toclaim 15 , comprising at least one patterned insulating layer on thephotocatalyst-containing layer, capable of displaying, by the emissionof light, a pattern corresponding to the part where the insulating layerdoes not exist.
 19. The EL device according to claim 18 , wherein theinsulating layer is made from an ultraviolet-curing resin.
 20. The ELdevice according to claim 1 , wherein the first electrode is formed on asubstrate, and the layer of a material whose wettability changes whenlight is applied thereto is a photocatalyst-containing layer, at leastone photocatalyst-containing layer being formed at any position betweenthe substrate and the second electrode, the photocatalyst-containinglayer containing a substance capable of improving light emissionproperties.
 21. The EL device according to claim 20 , wherein at leastone insulating layer is partially formed on the photocatalyst-containinglayer.
 22. The EL device according to claim 21 , wherein at least oneinsulating layer made from a photosetting or thermosetting resin ispartially formed on the photocatalyst-containing layer to make a part ofthe photocatalyst-containing layer on which the insulating layer isformed non-luminous.
 23. The EL device according to claim 20 , whereinthe substance capable of improving light emission properties comprises ametal salt.
 24. A process for producing an EL device which comprises alayer of a material whose wettability changes when light is appliedthereto, a first electrode formed on the layer of a material whosewettability changes when light is applied thereto, an EL layer formed onthe first electrode, and a second electrode formed on the EL layer,comprising the steps of applying light pattern-wise to the layer of amaterial whose wettability changes when light is applied thereto,thereby forming on the layer a latent pattern due to the difference inwettability, applying a first-electrode-forming coating liquid to theexposed part of the layer of a material whose wettability changes whenlight is applied thereto, thereby forming pattern-wise the firstelectrode, forming the EL layer on the patterned first electrode, andforming the second electrode on the EL layer.
 25. A process forproducing an EL device which comprises a first electrode, a layer of amaterial whose wettability changes when light is applied thereto formedon the first electrode, an EL layer formed on the layer of a materialwhose wettability changes when light is applied thereto, and a secondelectrode formed on the EL layer, comprising the steps of forming, onthe first electrode, the layer of a material whose wettability changeswhen light is applied thereto, applying light pattern-wise to the layerof a material whose wettability changes when light is applied thereto,thereby forming on the layer a latent pattern due to the difference inwettability, applying an EL-layer-forming coating liquid to the exposedpart of the layer of a material whose wettability changes when light isapplied thereto, thereby forming pattern-wise the EL layer, and formingthe second electrode on the patterned EL layer.
 26. A process forproducing an EL device which comprises a first electrode, an EL layerformed on the first electrode, a layer of a material whose wettabilitychanges when light is applied thereto formed on the EL layer, and asecond electrode formed on the layer of a material whose wettabilitychanges when light is applied thereto, comprising the steps of formingthe EL layer on the first electrode, forming, on the EL layer, the layerof a material whose wettability changes when light is applied thereto,applying light pattern-wise to the layer of a material whose wettabilitychanges when light is applied, thereby forming on the layer a latentpattern due to the difference in wettability, and applying asecond-electrode-forming coating liquid to the exposed part of the layerof a material whose wettability changes when light is applied thereto,thereby forming pattern-wise the second electrode.
 27. A process forproducing an EL device which comprises a first electrode, a first ELlayer formed on the first electrode, a layer of a material whosewettability changes when light is applied thereto formed on the first ELlayer, a second EL layer formed on the layer of a material whosewettability changes when light is applied thereto, and a secondelectrode formed on the second EL layer, comprising the steps of formingthe first EL layer on the first electrode, forming, on the first ELlayer, the layer of a material whose wettability changes when light isapplied thereto, applying light pattern-wise to the layer of a materialwhose wettability changes when light is applied thereto, thereby formingon the layer a latent pattern due to the difference in wettability,applying a second-EL-layer-forming coating liquid to the exposed part ofthe layer of a material whose wettability changes when light is appliedthereto, thereby forming pattern-wise the second EL layer, and formingthe second electrode on the patterned second EL layer.
 28. A process forproducing an EL device which comprises a first electrode, a layer of amaterial whose wettability changes when light is applied thereto formedon the first electrode, an EL layer formed on the layer of a materialwhose wettability changes when light is applied thereto, and a secondelectrode formed on the EL layer, comprising the steps of forming, onthe first electrode, the layer of a material whose wettability changeswhen light is applied thereto, applying light pattern-wise to the layerof a material whose wettability changes when light is applied thereto,thereby forming on the layer a latent pattern due to the difference inwettability, applying an insulating-layer-forming coating liquid to theexposed part of the layer of a material whose wettability changes whenlight is applied thereto, thereby forming pattern-wise the insulatinglayer, applying an EL-layer-forming coating liquid to the layer of amaterial whose wettability changes when light is applied thereto, onwhich the insulating layer has been formed, and forming the secondelectrode on the EL layer.
 29. A process for producing an EL devicewhich comprises a first electrode, a layer of a material whosewettability changes when light is applied thereto formed on the firstelectrode, a partitioning layer and a luminous layer formed on the layerof a material whose wettability changes when light is applied thereto,and a second electrode formed on the luminous layer, comprising thesteps of laminating, to the patterned first electrode, the layer of amaterial whose wettability changes when light is applied thereto,applying light only to a part of the layer of a material whosewettability changes when light is applied thereto that corresponds tothe part between the borders of the patterned first electrode, through amask having the negative pattern of the pattern of the first electrode,laminating the partitioning layer to the exposed part of the layer of amaterial whose wettability changes when light is applied thereto thatcorresponds to the part between the borders of the patterned firstelectrode, by utilizing the difference in wettability between theexposed part and the unexposed part of the layer of a material whosewettability changes when light is applied thereto, laminating theluminous layer between the borders of the patterned partitioning layerafter applying light to the entire surface of the above semi-finishedproduct, and laminating pattern-wise the second electrode to theluminous layer and the partitioning layer.
 30. A process for producingan EL device which comprises a layer of a material whose wettabilitychanges when light is applied thereto, a first electrode and apartitioning layer formed on the layer of a material whose wettabilitychanges when light is applied thereto, a luminous layer formed on thefirst electrode, and a second electrode formed on the luminous layer andthe partitioning layer, comprising the steps of forming pattern-wise thefirst electrode on the layer of a material whose wettability changeswhen light is applied thereto, laminating the luminous layer to thepatterned first electrode by utilizing the difference in wettabilitybetween the layer of a material whose wettability changes when light isapplied thereto and the patterned first electrode, applying light to apart of the layer of a material whose wettability changes when light isapplied thereto that corresponds to the part between the borders of thepatterned first electrode, laminating the partitioning layer to theexposed part of the layer of a material whose wettability changes whenlight is applied thereto, and laminating pattern-wise the secondelectrode to the luminous layer and the partitioning layer.
 31. Theprocess for producing the EL device according to claim 24 or 30 ,comprising the step of forming, in advance on a substrate, the layer ofa material whose wettability changes when light is applied thereto. 32.The process for producing the EL device according to any of claims 25 to29 , comprising the step of forming, in advance, the first electrode ona substrate.
 33. The process for producing the EL device according toany of claims 24 to 30 , wherein the layer of a material whosewettability changes when light is applied thereto is aphotocatalyst-containing layer.
 34. The process for producing the ELdevice according to claim 24 , wherein the first-electrode-formingcoating liquid contains a polar solvent, and the application of thiscoating liquid is conducted by a method selected from spin coating,ink-jetting, dip coating, blade coating, printing, dispensing, anddropping of the coating liquid on the photocatalyst-containing layer.35. The process for producing the EL device according to claim 25 ,wherein the application of the EL-layer-forming coating liquid isconducted by a method selected from spin coating, ink-jetting, dipcoating, blade coating, printing, dispensing, and dropping of thecoating liquid on the photocatalyst-containing layer.
 36. The processfor producing the EL device according to claim 26 , wherein thesecond-electrode-forming coating liquid contains a polar solvent, andthe application of this coating liquid is conducted by a method selectedfrom spin coating, ink-jetting, dip coating, blade coating, printing,dispensing, and dropping of the coating liquid on thephotocatalyst-containing layer.
 37. The process for producing the ELdevice according to claim 24 , wherein the patterning of the firstelectrode that is conducted after the first-electrode-forming coatingliquid is applied is effected by a method selected from a method inwhich the layer of a material whose wettability changes when light isapplied thereto is inclined before the first-electrode-forming coatingliquid applied is solidified, a method in which air is blown, and amethod in which an adhesive tape is adhered to the solidifiedfirst-electrode-forming coating liquid and then peeled off.
 38. Theprocess for producing the EL device according to claim 25 , wherein thepatterning of the EL layer that is conducted after the EL-layer-formingcoating liquid is applied is effected by a method selected from a methodin which the layer of a material whose wettability changes when light isapplied thereto is inclined before the EL-layer-forming coating liquidapplied is solidified, a method in which air is blown, and a method inwhich an adhesive tape is adhered to the solidified EL-layer-formingcoating liquid and then peeled off.
 39. The process for producing the ELdevice according to claim 26 , wherein the patterning of the secondelectrode that is conducted after the second-electrode-forming coatingliquid is applied is effected by a method selected from a method inwhich the layer of a material whose wettability changes when light isapplied thereto is inclined before the second-electrode-forming coatingliquid applied is solidified, a method in which air is blown, and amethod in which an adhesive tape is adhered to the solidifiedsecond-electrode-forming coating liquid and then peeled off.
 40. Theprocess for producing the EL device according to claim 27 , wherein thepatterning of the EL layer that is conducted after thesecond-EL-layer-forming coating liquid is applied is effected by amethod selected from a method in which the layer of a material whosewettability changes when light is applied thereto is inclined before thesecond-EL-layer-forming coating liquid applied is solidified, a methodin which air is blown, and a method in which an adhesive tape is adheredto the solidified second-EL-layer-forming coating liquid and then peeledoff.
 41. The process for producing the EL device according to any ofclaims 24 to 27 , wherein at least one of the first electrode, thesecond electrode and the EL layer is formed by vacuum deposition, andthe patterning of the vacuum-deposited layer is conducted by adheringthereto an adhesive tape, followed by peeling.
 42. The process forproducing the EL device according to claim 33 , wherein the unexposedpart of the photocatalyst-containing layer is water- and/oroil-repellent, and the exposed part of the same has increasedwettability.
 43. The process for producing the EL device according toclaim 25 or 27 , wherein the EL device is a full-color display, andpicture elements on the display correspond to the latent pattern due tothe difference in the wettability formed on the photocatalyst-containinglayer.
 44. The process for producing the EL device according to claim 25or 27 , wherein the first and second electrodes are formed pattern-wise,the EL layer is a luminous layer, and the application of light isconducted correspondingly to the pattern of the first electrode.
 45. Theprocess for producing the EL device according to any of claims 25, 27,29 and 30, wherein the luminous layer is laminated through at least oneof a buffer layer and a charge-transfer layer.
 46. The process forproducing the EL device according to any of claims 25, 27, 29 and 30,wherein the lamination of the luminous layer or the partitioning layeris effected by a method selected from ink-jetting, uniform coating, andpattern-printing.
 47. The process for producing the EL device accordingto any of claims 25, 27, 29 and 30, wherein the lamination of theluminous layer or the partitioning layer is effected by vacuumdeposition, and the film deposited on the unexposed part of thewettability-changeable material layer is stripped.
 48. The process forproducing the EL device according to claim 28 , wherein the insulatinglayer is made from an ultraviolet-curing resin.
 49. The process forproducing the EL device according to any of claims 24 to 27 , whereinthe photocatalyst-containing layer contains a substance capable ofimproving light emission properties.